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Coolant Pipe Replacement Detailed Instructions

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Coolant Pipe Replacement Detailed Instructions

I recently replaced the coolant pipes in my car. I needed to do the job myself because there was simply no way I was going to shell out anywhere from $1500 to $3500 in labor to have it done by the dealership or an independent shop. Plus, having read about the job, I knew they would be tearing through a ton of stuff and I really feared the "oh, it also needs this" scam. I did a LOT of research on the various forums before undertaking this job. Reading and printing out anything I thought was


Edited by jharness
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Thanks for taking the time to document all this extensive work. It will surely save someone a lot of money. I had to pay 2300 $ to fix that problem.

Thanks again.

I recently replaced the coolant pipes in my car. I needed to do the job myself because there was simply no way I was going to shell out anywhere from $1500 to $3500 in labor to have it done by the dealership or an independent shop. Plus, having read about the job, I knew they would be tearing through a ton of stuff and I really feared the "oh, it also needs this" scam.

I did a LOT of research on the various forums before undertaking this job. Reading and printing out anything I thought was useful information. I would highly encourage anyone reading this to do the same.

Fortunately, I was not in the position that the pipes simply failed and dumped all of the coolant. I just had a semi-slow leak… dropping about a gallon of coolant every two to three weeks. So, I had time to order the parts and prepare.

Prior to doing this the most complicated thing I had done myself was change the oil, replacing the brake pads and swapping out some plastic bits in the car. I had absolutely no prior mechanic experience whatsoever. However, I do work in IT, and am by nature a very technical person (I'm sure every mechanic reading this just rolled their eyes). My job is troubleshooting very complex problems on very large networks, and I think that experience probably lent itself to a successful outcome here. I'm also patient, and that is critical to getting this job done.

I will say that I now have a much greater appreciation for mechanics and their skill set. This was hard.

I want to caution anyone reading this that this is a BIG job and it will take a long time. My goal in writing this is so that my fellow Cayenne owners can be spared a lot of the mistakes I made and be better prepared than I was.

I will say I am relieved to have this done. I feel a ton better about my car now that I don't need to worry as much about some catastrophic failure hitting me unexpectedly.

One rule that I really appreciated was to only place metal on metal when working (until you actually get to removing the pipes). This prevents you from breaking plastic or tearing rubber with something metal. Trust me, pay attention to that rule.

I am breaking this down into tasks, because I think it's easier to follow that way. This is how I did it. I am sure there are other ways that may even be easier, but this worked for me and my schedule. I ended up working 4-6 hours at a stretch in the garage with breaks every couple of hours.

Step 1: Contribute to this forum

I have absolutely no affiliation with this forum whatsoever other than I am a contributing member. The advice on this forum has personally saved me thousands of dollars, and being in IT I know the time and money it takes to run a site like this. So, contribute to the cause.

However, there is a second reason to contribute, and that's to get the Porsche TSBs. The TSB for this job contains some diagrams that give you a better idea how all the replacement parts go in to place, and I thought that was handy to have. As an aside, I searched some other issues in the TSBs and found answers to some things the dealership didn't even know… such as there being a $33 replacement latch for my armrest. They wanted to sell me a whole new armrest for $750.

Step 2: Obtain the Parts

I looked around on the Internet and called some local sources and found a dealership that provided the parts for $550, and that included two gallons of coolant shipped to my door. To me, that was a fair price, and when I received the parts I really thought it was a fair price... there's a lot of quality stuff in there. I'm sure there may be cheaper 3rd party sources. I would just be sure they include all gaskets and such that don't necessarily need to be replaced, but should be replaced if you're tearing everything apart.

Once you get the parts, pull them out of the box and examine them. Look at the pics in the forum and look at the TSBs. Get a feel for what you are replacing.

Step 3: Verify you have the tools

I found the following tools very handy to have, and frankly, necessary. I suggest going to your local auto parts store for most of them and get mechanic grade tools.

Socket Wrench

3" Socket Extension

6" Socket Extension

Metric Socket Set

Torx Socket Set (think of this as a "male" Torx Socket set, you will need #27 & #40)

E-Torx Socket Set (think of this a "female" Torx Socket set)

Screwdriver that accepts interchangeable bits (there are times this is easier than a socket wrench)

Torx Bit Set (Specifically you need a #27 and #40, I just bought a set)

Locking Long Nose Pliers (6" is fine, no need for anything bigger)

Regular set of pliars

Wrench Set (somewhat optional)

Real flat head screwdrivers

Very long flat head screwdriver (this came in handy a lot)

Needle Nose Pliers

Small Chisel Set


Tin snips

Safety Glasses

Mechanics Gloves

One of those extension things with a magnet on the end

One of those extension things with a mirror on the end


Some all-purpose grease, like White Lightning

Baggies to store the screws in

Masking tape/Painters Tape to cover up any exposed openings

Old Bath Towels (used to protect the car)

Good flashlight

Lint free rags

Shop Vac

Two gallons of distilled water

Drain pan (needs to hold 4 gallons)

Shop lights

A small block of wood, about 2" x 4" x ¾"

A radio playing energetic music of your choice

Advil and Tylenol

Hope and a prayer (optional but doesn't hurt)

Step 4: Book the Time

I know some people say you can have this job done in less than 8 hours, but being a beginner this took me much longer. If I took out all the time running back and forth to the store for tools and such, and had a guide like the one I am writing, I still think it would have taken 10-12 hours.

I ended up removing all of the engine covers on one weekend night, and then doing the actual job the following weekend. I then drove the car for a week with the new pipes and finally put all the engine covers back on over the weekend (I cleaned the covers and the engine thoroughly with a damp rag at the same time to pretty it up a bit).

You don't really need to do it that way, but that split the work up a bit. I work in an office in front of a PC all day; I'm not used to working in a hot garage for 8-10 hours at a time... I'm a skinny computer geek : )

When I did the work, I draped some old bath towels over the sides and front of the car to protect it. The last thing I wanted to do was mess up the paint on a zipper or with a dropped tool/screw.

Step 5: Remove the Engine Covers

There are really two parts to this. You have the decortive covers over the actual engine, and then you have the covers that border the engine. You'll want to remove all of the covers around the border first. There are five of them in total. They all have these little black plastic plugs that you just turn 90 degrees. They should just pop up at that point, but you might have to give them a little lift with a screw driver.

While you're removing those covers you might want to pay attention to how they go together and where they slide in to place. You'll also want to remove the windshield washing fluid cap (use the masking tape to cover up the exposed hole) before you remove the cover that surrounds it.

Those little things are $4.25 each from the dealership, so try not to lose them.

Now you have the three silver looking decorative covers; one on each side of the engine and one towards the front middle with the engine type on it.

First, you need to unbolt the two secondary air injection units. Those are the round things with the plastic covers near the back of the engine compartment. You do not need to disconnect them from anything, just unbolt them (three screws each) and then move them off to the side. It might be a good idea to get some labeled baggies to store the screws in.

Once those are removed you can get to the side engine covers a little easier.

The engine cover in the front middle you just lift off, just work it back and forth a little and it should pop off. Take note that there are four little plugs that fit into holes on the cover itself, you'll need to find them again when replacing it.

Now remove the one on the driver's side. It's pretty easy to remove. There are four screws towards the bottom that need to be removed, and then the cover will just come off.

The one on the passenger side is a bit different. You have the engine mount right in the middle of things. Assuming you have the tools, you can unscrew the engine mount and get it out of the way. That will let you get to each of the four screws easily on the cover and remove it.

I wasn't so lucky here (didn't have the right tools at the time), so I just got the four screws out of the cover and ended up wedging it out. While doing that, the piece of the cover under the engine mount snapped off. I wasn't too concerned about this, because where it snapped is hidden by the engine mount. When I put everything back together I just slid it back and screwed it in. You can't tell at all that it was ever snapped in half.

Step 5: Remove Fuel Pump Fuses

You'll want to check your manual (you can also download the manual from this site), but you need to remove a couple of fuses for the fuel pump. Right in front of the driver under the hood there is a small compartment. Remove the cover, and then remove a second cover to expose the fuses. Mine were fuse 14 & 15 for the fuel pump. Store them somewhere safe.

Once those are removed, start your car. It will run for a few seconds and die. Congrats, you just removed most of the fuel from the fuel line. I know some people don't disconnect the fuel rail or anything, but to me that's a bad idea. I had a lot of time to try it that way and honestly I'm glad I got it out of the way.

Step 6: Disconnect the fuel line

The fuel line is near the back center, it's just one tube running to the fuel rail. You'll disconnect it by using a wrench and a pair of pliers. You're unscrewing the part on the left (the thin part) from the part on the right (the wide part) which shouldn't turn as it is part of that tube.

Once unscrewed, the fuel rail is only connected to the manifold. A little residual fuel might leak out, so you might want to have a rag handy to wipe it up with.

Use masking tape to cover up any exposed holes.

It wouldn't be a bad idea to disconnect the batteries now either. I didn't, but that was probably stupid.

Step 7: Remove the Y-Pipe that goes to the Throttle Body

This plastic Y-Pipe is right up front so it's very easy to get to.

There are two flexible pipes on either side you need to remove first; just use a screwdriver to loosen the two clamps on each of them and you should be able to compress them enough to remove them.

The Y-Pipe itself is attached to the throttle body via two long, plastic bolts. They have a screw head on them but they are not screws, they're more of a key. You just turn them a bit to line the key at the bottom (use a flashlight and you'll see it move as you turn it with the screwdriver) with the slot. When it's lined up, use a pair of needle nose pillars to lift it straight out. It's plastic and may be brittle, so be a little careful. You will need to remove an electric connection to the throttle body in order to get to one of them.

There is a tube connected to the bottom of this y-pipe, so you can't just lift it out. It has some give to it, but not a lot… just enough to get your hand under there once you pull the y-pipe off the throttle body. You have to press the buttons on each side of the tube in order to get it off the y-pipe.

Step 8: Remove Emission Tubes & Electrical Connections from Throttle Body

There are two emission tubes crossing the throttle body, Porsche refers to them as "vent tubes." I know this because one snapped in half when I removed it, and the dang thing was $130 to replace.

To remove them, you just need to press the clips at either side of the end of the tube together and then pull it straight out. I don't think mine had ever been removed, and in retrospect a bit of WD-40 used sparingly here might have been a good idea. I think I used too much force and that's why the small one snapped.

I have read that some people have replaced this broken tube with a more generic tube from a hardware store. I just spent the $130 and did it right.

There is a third tube connected to the throttle body, you just need to remove that one end of it.

You will also have two electrical connections to remove. One you had to remove to get the y-pipe off in the previous step. Just remove the second one and then you're done.

Step 9: Remove the Throttle Body

The throttle body is connected to the manifold via four bolts. Remove those four bolts and it will come off. You sort of have to wiggle it out because of that thin metal bracket that's holding it there, but it will come out easy enough.

Some people take this opportunity to clean it. You'll probably see some gunk on the back side of it on the inside.

Step 9: Remove the Electrical Connections to the Fuel Injectors

There are eight fuel injectors connected between the fuel rail and intake manifold. Mine were blue plastic, and there is an electrical connection running to each of them. There is a metal clip at the bottom that you just need to press up. I placed a flat head screwdriver between this clip and my index finger, and pushed up and pulled at the same time to disconnect it. Once you remove one you'll get the trick and the rest will come right off.

Step 10: Remove the Intake Manifold with Fuel Rail Attached

I know a lot of people have different ideas here, some people want to remove the fuel rail independently, and that was the first way I tried it. In retrospect, it's much easier to just leave it attached.

There are four screws that hold the fuel rail to the intake manifold. I would recommend leaving these alone, especially since the one at the back on the passenger side is nearly impossible to get to. These screws are $6+ each… I know because I lost one. :P

There are 10 bolts that need to be undone to remove the manifold. They don't come all the way out, they'll stay attached to the manifold. Once you loosen them enough they sort of come free and wiggle around. The one at the back on the passenger side was a bear to get to. I ended up placing the Torx Socket bit on top of it using the magnetic extension thing. I then put the 3" extension on top of it, and finally attached my socket wrench to it. I kind of built it all up I guess. I then went really, really slowly and loosened it up.

Once loose, make sure to vacuum up any debris on the engine. When you pull the intake manifold off you will have eight gaping holes right down to your cylinders, you don't want anything falling in there.

You can now scoot it forward a bit to get to the tubes you will need to disconnect.

There are two tubes at the back of the manifold… a firm one and a flexible one. The firm one is just like the one under the y-pipe, and is easy enough to remove IF you can get enough pressure on the connector. The flexible one was just kind of stuck on mine and I left it on.

You kind of have to scoot the manifold forward and angle it out, but it will come out with the fuel rail attached. You may have to remove some tubes and such from their guides or brackets. That flexible tube was long enough that I just put the whole thing on the driver's side of my engine and left it there. It didn't seem to be sitting on anything that couldn't support it. I'm sure it can be removed, but at this point in the job I was tired, hot, and just wanted to keep going.

Once off, IMMEDIATELY cover up the exposed intake holes with long strips of tape. Cover them completely, and make sure they STAY COVERED. Shine a flashlight in each hole first to make sure nothing fell down there. If so, get it out as delicately as possible. Vacuum up any other debris you see.

You can now see the infamous coolant pipes.

Step 11: Assessment

At this point, you can see the coolant pipes and should be ready for the meat of this repair. The starter is right there too… right under the leaking pipes. Brilliant, isn't it?

This may not be true for you, but I had an AMAZING amount of debris in here… honestly looked like a bird had built a nest. I have no idea how it all got in there, but some where at some point tons of debris got in here, and now it was all soaked in coolant. I think my coolant leaking may have been mitigated because the wet debris probably acted as a mud and sealed everything up a bit.

I vacuumed it up with a shop vac prepped for a wet cleanup.

Now you need to decide if you will see this repair through or not. Once the next step is taken, there is no going back, and honestly the toughest part of this job by far is getting the old pipes out.

Step 12: Drain the Remaining Coolant

Your first goal is removing as much coolant from the car as you can. On the V8's, there is a drain plug at the bottom of the car, but on the turbo's you won't have one. That drain plug required an alan bit that was larger than I had on hand or could even find at a hardware store. Honestly, in retrospect I wouldn't have even bothered locating it. I'm sure there's a pipe down there you could remove, but I didn't waste time looking for.

I took a tip I found on a forum, and drilled a hole right in the middle of the center coolant pipe (of three) and used a siphon with a hand pump to drain out every bit I could. I repeated this process on the larger lower pipe. DO NOT SIPHON BY USING YOUR MOUTH. Coolant is dangerous, nasty stuff. Make sure there are no animals or kids around while you are doing this. WEAR SAFETY GLASSES AT ALL TIMES!

Doing it this way you're going to spill a lot of coolant, but it is what it is… they've been leaking all over everything anyway. I used my shop vac to vacuum up anything I could that escaped the siphon.

I've also read of people renting professional vacuum pumps to suck it all out, but again, that's more complicated than it needs to be.

I did some research, and coolant is not currently controlled by the EPA for disposal, and it can't be recycled. The unofficial advice I got was to dump it in the woods and douse the area with a hose for a bit. Do not dump it down the drain or dump it where animals could readily drink it. Don't dump it in a stream. Presumably it breaks down fast enough on the ground that there isn't a long lasting effect.

Step 13: Remove the Three Upper Coolant Pipes

The first pipe you need to remove is the long skinny pipe with three connectors. This one is easy enough to remove, and you should have a replacement as part of the kit. One of the connectors broke off in the hole, and I had to very carefully remove the pieces. Relatively speaking this was easy compared to the rest. There is a compression ring that needs to be removed for the connection at the back of the engine, use the locking pliers to do that.

Cover up the exposed holes with masking tape.

You now have to remove the three upper coolant pipes. There is a bracket at the back of the engine holding the three pipes. There are also two clips attached (you'll be looking at the back side of them) to that bracket that just support a hose at the back (just has electrical connections in it, and it's probably already split so you don't have to be super careful). Pinch the connectors with a pair of needle nose pliers and they'll come off.

You now have to remove three bolts from it to remove the upper half of that bracket. I removed two of them but couldn't get to the third without snapping the thing in half. Porsche was kind enough to provide a new one in the kit so I wasn't worried about it.

You will now see three rubber hoses attached to the plastic pipes. They are held on to them with compression rings. Use the locking pliers on the rings to loosen them (they need to be squeezed together to loosen) and slip them back over the pipes. I did one at a time, completely removing the ring and setting it off to the side for safety.

The locking pliers really excelled here. When using them, attempt to come at the ring from the top instead of the side, the grooves on the pliers will then secure the ring quite nicely. You might have to adjust the pliers a couple of time to get the right amount of the compression for the ring to move freely.

With those ends free, I used the shop vac to suck out a lot more coolant. Once done, cover up the exposed holes with masking tape.

Once those three ends are free, you'll need to free up the other ends. Here's the deal, they are probably going to break when you try to remove them, and probably going to snap off at the spot where they connect to the coolant reservoir. I twisted and pulled and sure enough, they snapped off.

You can remove the lid of the coolant reservoir by removing several screws, a small aluminum pipe on top, and the rubber pipes towards the front of the car.

The small aluminum pipe has a single screw that needs to be removed. There is probably a lot of corrosion here so you may need to use a flat head screwdriver to pry it out. Be careful, it's flexible enough to come out and get out of the way but just barely.

There is a compression ring on each of the rubber pipes that is easy enough to get to, just loosen and slide it down the pipe. Suck out any coolant and cover the exposed pipes with masking tape.

Once you have that lid out, you'll see the remaining plastic bits in the holes. It's difficult to move, but those plastic bits are just in there with pressure, they aren't glued or anything. I used a small chisel and the hammer to break them out. As I got to the o-rings I pulled on those with needle nose pliers and in one instance the whole chunk came out. I also used a lot of WD-40 to work everything out.

What you don't want to do is take any risk of chiseling into the metal of the lid, so be careful. This is all about removing the plastic material. Each bit you remove gets you one step closer to freeing up enough pressure to get the remaining bit out.

Once it's all clean, leave it off to the side while removing the big pipe.

Step 14: Removing The Big Pipe

This one is tough. Make sure you're rested, well fed, and cooled down a bit. If you're aggravated already, walk away and relax a bit.

You will need to break this pipe into two pieces. I used a boring bit to drill a big hole in the top, and then used tin snips to cut chunks out until I got it in two parts. Again, I used a shop vac to suck out any remaining coolant as I went along.

Really, anything will work… you could even use a chisel to break it out. It's coming out one way or the other, no need to be pretty about it.

Once it's in two pieces, you can probably rotate the two halves apart. Use WD-40 generously on the ends first though, and give it a bit to work in there. Regardless, when I went to pull out the two ends, they ended up snapping off… leaving their end pieces in the hole. If you read through the three forums, different people use different techniques to try and avoid this with mixed results. This is the worst case scenario though, so lucky for you I fought through it and have plenty of advice.

Assuming your pipe broke off as mine did, you will see a metal ring in each end, with black plastic between it and your car. That metal ring was an inner support ring for the original pipe and needs to be removed. This is a violent procedure.

IMPORTANT: I cut up some lint free cloths and stuffed one into each end as far as I could so that any material from the following procedure wouldn't go any further. Once done with the procedure below, I vacuumed up anything I could and then removed those cloths.

Again, use WD40 a LOT. I sprayed and sprayed as a worked, and I think it helped.

READ THIS CAREFULLY: Removing the plastic and metal ring from each end is all about removing material. You are trying to get as much plastic out as possible. If you get the ring out first, great, but it's not 100% necessary. The plastic is what needs to come out, and you need to get it out from all around it. In addition to the plastic, there are two o-rings in there, so they are just adding more friction preventing this from moving. You'll get bits of that out as you work, and that's good. Eventually, you get enough bits out that the rest will just fall out.

Use a hammer and chisel to collapse the metal ring on the top and sides as much as possible. I used to the chisel to cut in to it a bit too. Once I got it that far, I switched to the long screwdriver, hammering the end of it into the plastic over, and over, and over again. I pried as much as I could and worked out bits of material. This took a long time, but sometimes you'll get a big chunk out and that will give you renewed hope.

Again, this is all about material removal. Keep telling yourself that. Every bit you get out makes this easier. Once you get enough plastic out, you'll see the metal ring move a bit as you work. This is a great sign and you are almost done. Ultimately, you should be able to pry it out with the screwdriver.

NOTE: When working you want to work as much towards the metal ring as possible. You want to avoid scraping the inside of the hole where your new pipes will go. I did scrape up mine a bit, it's unavoidable, but regardless my new pipes don't leak.

When you go to remove the bits closest to you, you're working somewhat blind and it is hard. This part almost broke me, but I used a mirror to check and recheck my work as I went along. Bright lights help here too.

Honestly, I really can't say enough how hard this part was and how long it took in comparison to everything else. It was the part that had me the most worried, but I got through it.

Once it's all out, remove the cloths from inside the pipe and vacuum a lot. Now is the time to clean stuff up too, as you're about to put the new pipes in.

As a best practice, you should clean up the inside of those holes. I used some steel wool; I know some people used scotch bright or even buffing pads. I didn't go overboard with this; I just want to get any grime out of there.

Step 15: Install the New Big Pipe

At this point you should be elated. You're through the worst. Installing these pipes are a bit difficult, but not bad.

If they are not already on there, put the O-Rings on the small pipe. Use the White Lightning grease or whatever you bought and coat the inside of the hole on the engine and the outside of the pipe. Use it liberally. A bit of WD40 wouldn't hurt either.

Press it into the hole at the back of the engine and do your best to get it all the way in. This is where a small block of wood and a hammer come in handy; you can use those to tap it in the rest of the way. Do not put the rubber sleeve on it.

For the big pipe, install the o-rings and lube everything up good with the grease, both the hole it goes in and the pipe itself. You will also need to grease up the end the rubber part goes on and the other end of the short pipe that the rubber sleeve will slip over. Place the tightening rings over the rubber sleeve as well. Slide the rubber sleeve as far as it will go over the pipe.

Push the pipe into the hole, I found a twisting action worked well. I also used my metal screwdriver against the bottom of the engine bay as a lever to slide it in the rest of the way (it required a lot of pressure). You then need to rotate it to line it up with the short end of the pipe. You'll slide the rubber sleeve over it and then tighten up the two rings.

NOTE: Be sure to rotate the rings as far down as possible so that the screw does not interfere with the three pipes you're about to place on top of it.

The new big pipe should be in place, and you're now done with the hardest part of this job.

Step 16: Install the Three Pipes

You'll want to put the lid back on the coolant reservoir (replacing the seals Porsche included with the kit), reattach the pipes and tighten up the screws. DO NOT OVERTIGHTEN THE SCREWS. I snapped one clean off. Make sure they're tight, but don't put all your muscle into it.

Once on, you are ready to slide those pipes in. You do not need to put the lower bracket at the back on first; I did it after installing the pipes.

Again, make sure everything is lubed up well so that any points of friction are well covered.

Slide the pipes in. I used by long screwdriver again as a lever to apply the necessary pressure. On both these pipes and the big pipe it looked like I could have gone another 16th of an inch, but nothing leaks so I guess it was far enough.

Put the bracket on at the back before you attach the hoses. You'll use your locking pliers again to attach the compression rings. With the bracket in place it is obvious how far up the hoses go.

You'll put the upper bracket on, using the spacers for the screws and screwing it down tight. Don't forget to attach the two brackets that hold that electrical cable in place. Not a big deal if you do forget.

Step 17: Install Final Pipe

Now install that skinny pipe. This one is easy. Don't forget about the small compression ring that goes at the far end. Everything else just clips in.

Step 18: Assess Your Work

Look over everything and make sure it all looks right. At this point you should have a sealed coolant system. Check all your connections and make sure everything is solid. At this point you're home free, and you should be feeling pretty darn good.

Step 19: Fill Up Coolant

I use a 50/50 water to coolant ratio… so I mixed everything up with what I had and filled up the coolant tank. Once it was full, I left it overnight and checked in the morning for any fresh coolant. I was totally beat from a long day of working on it and thought putting everything back together fresh in the morning was a good idea.

Step 20: Put Everything Back Together

You tore it apart, now put it back together. I cleaned everything as I went, so now my engine looks great and I think that's a good idea. You don't need to go overboard, just use some lightly damp, lint free rags and wipe everything down.

Porsche should have also provided new seals that go on the bottom of the intake manifold. I replaced mine dutifully, and I am glad I did. The old ones just looked worn out, no way they weren't leaking.

Putting everything together is pretty straightforward once you've taken it apart. Just be careful and make sure you get all electrical connections and hoses in back on securely and in the right places (hard to mess that up). Also make sure you remove every bit of masking tape as you go.

Final Thoughts

I am very, very glad I did this project for two reasons. One, it saved me a ton of money and two, I now know tons more about the engine. Doing this project means I could replace my fuel injectors, spark plugs, injection coils and a host of other things when and if I have to. I know where the throttle body is, and if it's sticking I know where to go to clean it. If I need to replace the starter, I know where it is and how to get to it.

I can now take my car on trips without fear of a massive coolant leak. This was the last "major" Cayenne defect for me that needed to be fixed. The water pump & drive shaft were already replaced. With 116,000 miles, I have quite a bit of faith in my car not having a catastrophic failure (knock on wood).

At the end of the day, I'm pretty proud of myself for getting this all accomplished, and I hope I've saved some other poor soul a ton of time by writing all of this down. If it does help you out, please reply to this post and let me know.

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Great job on the write up. I am also an IT guy and having an analytical mind certainly helped me in a couple of places. I broke the short vent pipe fron top of the engine and also the longer emmisions pipe on the left side-mainly because they were extremely brittle. Replacing both of those cost about $180 but Im glad I did because it also resolved a long standing problem with an intermittent check engine light. The funniest thing was when replacing the inlet manifold I suddenly realized that I hadnt removed the masking tape from the head....now that could have caused some starting problems! Good advice on taking lots of breaks, especially when working in high temperatures as it will lead to mistakes and rework if you dont.


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Thanks much for the DIY - it was used extensively today. Did the job today with my friendly independent (I hold the light, hand tools, pull on things when needed, bring coffee...)

This is a fairly intense job. Unless you're a dedicated DIYer - I'd look for some professional assistance. Biggest ugliest part of the job is getting the old big pipe out. That alone took about 3 hours. The rest of the job isn't awful - just a lot of dissembling and reassembling. I can't emphasise how big a PITA it is getting the stubs of the old pipes out. I thought about the possibility of some sort of puller (like an expanding internal bearing puller) to pull the **** things out. Wonder how the Porsche techs do it.

Did find enough corrosion on the openings where the new pipes go to see that the primary O ring had allowed some coolant past, and it was just the secondary ones that were preventing leaks. There were no leaks, which was a good thing, and the pipes actually weren't at all brittle (actually they appeared just fine..) The small pipes weren't a big problem to remove from the thermostat housing cover - used a vice and some big channel locks, and twisted/levered them out.

Because of the corrosion in the bores (which we cleaned up as best we could with sandpaper) we used RTV sealant on all the fittings as we reassembled, except the short rubber tube that seals the two halves of the big pipe - that got the Porsche magic $25 grease. It's sitting overnight to let the RTV set up and will be pressurized and finished filling it in the AM. It would mean it would be more difficult to get apart if it needed it - but knocking on wood - I hope it never does.

I took a bunch of photos which I'll post with some comments when I have a chance to download them and do a bit of editing.

Items missing from the kit I bought (Sonnen Porsche.. the $350 one on their website): the O ring for the small metal pipe on the front of the thermostat housing cover. Used RTV on it. The intake manifold gaskets. The magic grease. A seal fo the throttle-body to intake manifold. And of course the horribly expensive Porsche coolant (which is probably relabled GM stuff..) And the hose clamps for the short length of tubing connecting the two halves of the big pipe (size is 30-40mm). Possibly unneeded: The bracket for the heater hoses - old one and new one looked IDENTICAL despite having a new PN; the emissions hose that goes over the top of the pipes - we replaced it since we had a new one, but the old one looked perfect.

Edited by deilenberger
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I've been keeping an eye on my coolant level all day, and smelling the engine compartment.. :unsure:

Yesterday I drove it about 30 miles locally, then let it cool and checked the coolant. It was right at the minimum ring on the level indicator. I topped it up to the MAX ring. The difference is about a pint. After running it today, I checked and when hot it was about 3/8" above the max line (but not up to the cap level where it would burp out..)

From reading the service manual on cooling - they show the level ring being read when the coolant is cool, so I'm guessing my level is OK. Went about another 40 miles today, and no signs of any leakage I can see. I could smell coolant evaporating a bit this AM - but that isn't a surprise since the valley under the pipes is actually rather deep, and looks like it can hold a lot of coolant before overflowing to the bell housing area. There was some coolant that remained in the valley after changing the big pipe out, despite my best efforts at sucking it up with rags and paper towels.. so I think that's what I was smelling evaporating today. Since this was well below the level of the starter it wasn't a big concern.

The smell greatly diminished as I used the car and then ran it through the local carwash (which ate my rear-wiper arm.. another story..) Didn't smell anything at all when I got home from dinner out (Fatheads day!)..


Interestingly - I found a repeated warning in the service manual section on cooling - to not open the system when hot (not an unusual warning - due to fear of scalding) - but also warning to let the system completely cool off before closing it IF it is opened when hot. The claim is made that "severe damage to the cooling system components" could occur. The warning has me totally baffled. The service manual describes using a vacuum system to bleed air from the cooling system (first evacuating the system, then injecting coolant into the under-vacuum system) so I can't see any slight vacuum formed as the coolant contracts when it cools being a problem, especially if the reservoir coolant cap is working correctly (it's supposed to let air INTO the system when a vacuum forms due to cooling.) It's a very puzzling warning to me..

Update - I asked my mechanic about this warning, he said he's seen it before. Apparently if the system is closed and the engine started before cooling off an air bubble can form in the system due to the minor vacuum pulled on the system. If the air bubble happens to be someplace like the water pump - this can cause rapid overheating due to the lack of coolant circulating.

Update 2 - Wiper arm. As is not uncommon, it broke off in a car wash (despite being taped down.) Kudos to Rain Tunnel car wash on Rt 71 in Bradley Beach NJ and the owner Mike Conti. I contacted him this AM from the car-wash, and he immediately came down. He saw the truck, and said "We have to fix that.." He had the local Porsche dealer on speed dial and was friends with the service manager - turns out he has owned several Porsches. He said to the service manager "I'm sending a customer with a Cayenne-S down, fix his rear wiper.. and charge me." He then handed me a number of complimentary free car-wash coupons. I went to the dealer - they replaced the arm and the wiper, and said "Thank you for letting us serve you.." All around - a quite pleasant experience. I highly recommend Rain Tunnel Car Wash in Bradley Beach, it's owned by a decent and reputable businessman!

Edited by deilenberger
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Thought I'd add some images to this excellent DIY:

Tools and impliments of destruction: The tool on the right is a Chapman ratcheting hex holder from a Chapman tool set. I have several of these left over from decades ago, and find them about the most useful tool I own. The ratchet accepts standard hex/torx/screwdriver 1/4" hex-drive bits, and accepts a magnetic extension. Hard to beat for removing the multiple Torx fasteners used on the P truck.


Area prepped for initial exploratory surgery:


Gotta remove this screw (T-10):


Plastic decorative panels removed:


Passenger side air-pump - remove:


Driver side air-pump, remove from bracket:


Using Chapman tool with torx bit and extension to remove decorative cover screws:


Chapman tool in tight quarters - no extension used:


More tools needed: E-Torx and Triple-Square drivers"



Edited by deilenberger
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The continuation of day 1 - plastic removal..

Using the Triple-Square driver to loosen the engine brace bolt. The other end of the bolt has a 16mm nut on it. Use Loctite BLUE medium strength when reinstalling it.


Brace moved out of the way. The nut on the body side must be loosened to swing it up.


Loosening the air-pump mounting so I can pull it up just a bit: This takes an E-Torx-10mm (external Torx 10mm).


Which allows me to wiggle the plastic beauty cover out from under the brace-mount. This cover comes out at an angle, and feels like it is going to break. So far it hasn't. The factory service manual shows exactly this technique for removing it. If it didn't look a bit crude, I'd leave both valve-cover beauty plastic covers off.. engine would probably run cooler, be lots easier to do coil/plug swaps and wouldn't have this chore to do whenever you want to get to anything:


And that was the end of day 1 - it took about an hour to get to this point. I refastened the air-pumps to their brackets, making the truck driveable, took it to my mechanic to leave it sit overnight and cool off so it could be worked on the next day.

Edited by deilenberger
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The next morning, by the time I got to his shop - my mechanic friend had the intake manifold removed and out of the way. Fuses 13 & 14 were removed to disable the fuel pumps (check your vehicle fuse listings to make sure it's the same ones on your truck), the fuel line disconnected, a bunch of hoses moved out of the way, the Y pipe, MAFs, and intake throttle body were all removed, followed by the manifold with the fuel rail and injectors left attached. The intakes were stuffed with paper towels, and deeper surgery is about to occur.

First a view of the existing pipes:


Look good don't they? There were no leaks, the pipes were still resiliant (not brittle) and all looks well.

The manifold sitting on a bench.. the bolts are captive so no fear of loosing one down an intake. You can see the fuel line connection on the other end of the manifold.


Closeup of the old pipes:


After cutting off the ends of the top pipes near the thermostat housing cover:


Sorry - No shots of the big pipe cut up - and drilled and attempted removal. It's not coming out without a lot of force and bloody knuckles. The rings used to reinforce the ends of the plastic pipes are thick stainless, and don't give up without a fight. Once those are gotten out (using chisels and screwdrivers and large pliers) the plastic bit pulls out fairly easily.

This is what was left of the end that went into the thermostat housing:


The other end still in the cylinder-heat cooling manifold:


And after removal (and cleaning up of the bores) - the first NEW fitting goes on the engine.

Note the RTV used along with the new O rings to make certain there are no leaks. While the old pipes looked good - the O rings looked less good. There was dried coolant between the two O rings, meaning the innermost one had started allowing coolant past. I would guess that before long the outer one would have also deteriorated to the point of allowing leakage. I think this is simply an age/heat/time thing. The hope is - the RTV sealant will help seal this joint even better, and the aluminum pipes should never need removal.


The other end of the big pipe in position with the rubber stub still back on the pipe:


The pipe in position, with clamps holding the rubber hose stub in position.


The end of the big pipe that goes into the thermostat housing - also sealed with RTV and the two O rings.


Edited by deilenberger
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Details of the upper heater hose stubs. Note the condition of the O rings. These were removed without major damage to them by clamping the end of the tubing in a vice, and rotating the thermostat cover while pulling away from the hose. The O rings are not in great shape, although there was no leakage seen. It does appear it was around time to replace them.


All the parts getting roughed into position. The pipe being moved is the one that goes into the front of the thermostat housing (facing the water pump area) and the pipe goes down to the alternator to cool it. This pipe has two O rings that seal it up - neither is included in any kit I can find. I'll post the PN's here when I have a chance. The O rings should be replaced when this job is done but I suspect rarely are since Porsche didn't include them in the service-bulletin "kit" listing. Since we didn't have new O rings to use - the pipe also received a good layer of RTV, including under the face-flange that holds it into the thermostat housing.


All the plumbing is in place now.. :rolleyes:


Closeup of the generator cooling pipe - with RTV used generously to assure it seals up well:


And the intake manifold goes back on:



The truck sat overnight again, so the RTV could "set" - and was filled and bleed. Eventually it went home with me, and all the plastic went back on. It's running quite happily at 180F, and has taken about 1 pint of additional coolant to top it off.

Hope the photos are useful!

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No problem. Wish I'd taken more. If someone around the NJ shore area is going to do the pipes - let me know, I'll be over with the camera to fill in the gaps.

It's a week now - the coolant level has settled nicely (I check it in the AM - engine cool - and after setting it midway between MIN/MAX - it hasn't changed at all.) I still have a wiff of coolant smell, but I suspect that's just from spilled/leaked coolant - the smell has diminished day by day. Tonight I washed down the engine, engine compartment and underbelly (just using plain water from the hose) - then warmed it up - and no more smell that I could sniff.

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  • 1 month later...
  • 2 weeks later...

Is there a special procedure to bleeding the cayenne coolant system. Some cars I find are simple (my 500sl is a doddle) but others are a paint to get the air out (many bmw's). I'm starting this job tomorrow and it doesnt look too challenging at all thanks to this guide. Im used to building engines and so on so I think this should be ok.

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  • 2 months later...
  • 2 months later...

Hi everyone, I'm new to the board and the coolant pipe club as well, as of last Thursday. My pipes failed on the highway, the first day of vacation on the way out for a snowboard trip.

I got the kit from Sonnen and it included just the right amount of parts (sans coolant). My advice would be to check the gaskets first because mine were perfectly intact.

I printed out this page as a reference and worked closely with my mechaninc on this one. I was most concerned about the large pipe after reading everyone else's ordeals and wanted to offer my recommendation.

If you have a steady hand, and a torch, heat the ends of the pipes and soften them up against the aluminum. They pry out within minutes and it'll save you some bloody knuckles and a lot of time!

All said and done it was a 4-5 hour job.

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  • 2 weeks later...

You guys are great. This forum has described the fixes for every single strange hard to pinpoint problem I have encountered on my cayenne s. Rough idle, starter noise, etc. I will contribue 5% of the money you saved me after I total up my pending coolant leak, starter, fuel filter, spark plug service!!! If you are ever in Milwaukee, the drinks are on me.

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  • 3 months later...

I just ran through the steps, minus the pipes, to replace the starter in my CTT after the bendix decided it was going to stick every second time I started the car and suddenly stopped engaging altogether. I reinstalled the intake manifold, torqued everything down properly and reconnected all the electrical and vacuum lines, and its idling up to 12-1300 RPM. Now if I give it some throttle and then release it, it drops to 500 RPM and misfires, and restarts the high-idle almost immediately. I figure its a leak at the intake manifold gaskets - I had to reuse the old ones because my supplier had them on backorder. I know it wasnt a very good idea, but I thought it would be worth a shot if it would get me through the week. Definitely not going to drive it as is, was wondering if this sounds about right or if I should be looking elsewhere like the vacuum lines/injectors? Coil packs and plugs were done barely a month ago.

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  • 1 year later...

Important: This was not mentioned in the original post neither does the "upgrade kit" contain any indication to this: But you should really replace BOTH thermostat gaskets (the outer and the inner one) in case you have dissasembles the thermostat housing to get the plastic pipes out. Also make sure to clean the old plasic rest in the three holes with some kind of sand paper. Torque back the thermostat housing with 7.5 lbs-ft or 10-11 NM. Not more!

Just another hot tip for those who are having problems with getting the larger pipe out:

Let's assume you have already cut/broken/whatever the pipe in half and you have still problems getting the pipes out ... here might be a way to go.

Drill a very large hole right through the pipe: Means you enter at the top and drill as long as you exit at the bottom. Now you can stick a large metal bar (or a long screwdriver) all the way through the pipe and use it rotate the pipe back and forth. The longer the metal bar is, the easier you will be able to rotate, so think about getting something as long as possible. After like 15-20 minutes of rotation the pipe fell of leaving the metal ring there for further "work" :king:

This is how i mean it. Worked pretty well: After trying around with a pair of pliers for around 2 hours i finally made it with this solution :-)


Edited by IchBinEineNudel
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  • 8 months later...

A couple of tips regarding the coolant pipe fiasco:

1. If you damage the (brittle) vent pipes during the coolant pipe job, just get yourself some 1" heat shrink tubing. Slip each of the broken ends into the heat shrink and warm it with a heat gun and you'll have a good repair and save $180. There's no pressure inside these lines. My Porsche mechanic tells me he's fixed lots of vent pipes with heat shrink. Works like a charm. I have tried to download some photos but the maximum file size is 2mB and even my pocket camera makes files bigger than that!

2. Assuming that you didn't lose all of the coolant in the car when the pipe(s) failed, it's hard to get the rest out. My 2006 Cayenne S radiator does NOT have a drain plug! You have to unhook one of the large diameter rubber hoses - and you'll make a huge mess doing so. I just added coolant to whatever was left until the system was full. It took a bit more than a gallon of the (ridiculously expen$ive) Porsche coolant to top it off.

3. The silver plastic beauty covers that say "Porsche" on them and cover up the coils are a real pain to get in and out. I just carefully sawed each individual cover off with my shop bandsaw and then put them back on one by one. Unless you're VERY familiar with the underhood area of a Cayenne, you'd never notice the difference. Again, I have photos but the 2MB limit on download size won't let me attach them.

I've owned eight 911's, two 911 turbos and a 356 over the years in addition to this Cayenne. Every manufacturer makes some mistakes, of course. But the Cayenne really takes the case. As just one example, the four bolts that hold the engine torque brace to the cylinder head are two DIFFERENT sized bolts, thus requiring two different sockets. I've got the sockets - but why?? Really dumb design abounds everywhere on this car, and Porsche should be ashamed of it. My Porsche mechanic tells me that the newer ones are even worse! I won't ever buy another Cayenne, that's for sure.

How are the wonderful photos of this repair accommodated? Surely they must be > 2mB.

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Dan - assuming you are using a Windows based PC - you might look into the free program "irfanView" (Google it) - and use it to resize your photos. If you set them for 1024 pixels wide - the file size will be reasonable and they won't cause a horizontal scroll bar for the viewer of the image. If you're using a MAC - dunno - you're on your own. Most Android phones come with image editing software that allows for resizing of images, and for the option of taking images at different resolutions. Again - 1024 pixels is pretty much a standard.

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  • 2 years later...

I've just completed the coolant pipe job on my C'S.  I'm going to replace all the coolant and distilled water hover does anybody know how to fill without a vacuum.

Ive ran it with the old coolant and water tipoff to check the integrity to find that the top radiator hose isn't getting hot at all aven after almost an hours worth of idle, fast idle and revving up.  

The cabin heaters eventually got toasty hot but do cool slightly on tick over.


I don't mind draining the system and replacing every couple of years to protect the internals

(using more modern Prestone all car formula 150,000 miles or 10 years).  

From a mechanical point of view I never believe the lifetime fill done when it was made in 2004. 

Maybe it explains why Porsches have water pump failure.   Oddly, in a million miles of driving only my first car failed in the first two days of ownership twenty odd years ago.   Since then even the two Grand Cherokee are all original with Mercedes CRD i5 and V6 diesels. 

Where is the self venting or the bleed valve?

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4 hours ago, Penguin said:

I've just completed the coolant pipe job on my C'S.  I'm going to replace all the coolant and distilled water hover does anybody know how to fill without a vacuum.

Ive ran it with the old coolant and water tipoff to check the integrity to find that the top radiator hose isn't getting hot at all aven after almost an hours worth of idle, fast idle and revving up.  

The cabin heaters eventually got toasty hot but do cool slightly on tick over.


I don't mind draining the system and replacing every couple of years to protect the internals

(using more modern Prestone all car formula 150,000 miles or 10 years).  

From a mechanical point of view I never believe the lifetime fill done when it was made in 2004. 

Maybe it explains why Porsches have water pump failure.   Oddly, in a million miles of driving only my first car failed in the first two days of ownership twenty odd years ago.   Since then even the two Grand Cherokee are all original with Mercedes CRD i5 and V6 diesels. 

Where is the self venting or the bleed valve?


The cayenne v8 is a bit of a bi*ch to bleed air without the right equipment but it is doable. 

For starters be real careful as driving around with air in the heads will just give you blown head gaskets real soon. 


To get air out there are a few tricks I found worked, the heaters needs to be on full hot and assuming the thermostat is working, no blockages, and the water pump is good here we go. 


1. squeeze the radiator top hoses with the expansion cap off (requires cold coolant startup for this and mine your fingers on the rotation belt and rad fans) you will find one pipe is cold and the other is hot because the thermostat is not open yet, keep squeezing and topping up coolant so it doesn't suck air in via the expansion tank. I found an alternating squeeze sequence worked well when both pipes where warm. 

As the coolant warms up the other hose will get warm and even more air will bleed if you keep squeezing hoses. 


2. If you have rear AC (4zone) you also need to help that bleed too, under the car driver side (lhd) is metal plate under panels (maybe different of yours) remove panel and you will see water pipe and AC refrigerant. Squeeze the hose and you will feel the air purge out and heat start to circulate through the exchanger. Some uphill parking engine bay up of course will a jack lifting the passenger side where the expansion tank (handbrake on, bricks behind rear wheels) is will also help. 


3. Lastly when you think all the air you can get out is gone and all the coolant you can force in is in then you need to drive it up to temp and then cool over night. Next day unscrew expansion tank and surely the level will be down, top off and repeat for a many days as it takes to see the level stay at max. Keep those heaters on hot! 


Failing all this hassle get a vacuum bleeder!

But sometimes even with the bleeder you still need some of the above to get all air out. 


Caution when the coolant gets warm the expansion tank will start to spill over as the air pushes it out and the water starts to boil without the aid of the pressure which should be built up if the cap was on. Before the coolant spills over you need to put the cap on quickly and shut off engine to cool. After cooling open and squeeze hoses again with engine off this time, top up, then close and go for a drive always monitoring the temp gauge. 

Man... This is time consuming!

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