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I spent the weekend on major maintenance:

I attempted:

1. Cabin Filter (no issues)

2. Oil change (no issues)

3. Power steering fluid (question)

4. Front Rotor Change (no issues)

5. Brake fluid bleed (question)

6. Clutch fluid bleed (no issues)

7. Radiator and A/C Heat Exchanger clean-out (note of caution)

8. Spark Plug Change (major problem)

9. Cabin Filter (no issues)

All parts were ordered from Sunset Porsche.

Power Steering fluid:

I could not figure out for the life of me what the purpose of the small rubber cap on the side of the reservoir? I just extracted what I could from the reservoir and then filled with Pentosin, started the car, turned the wheeel end-to-end several times and then repeated 5 times. I don't know if there's another way to swap the fluid.

Brake Fluid bleed: (I used 1 liter)

The instructions in one of the threads call to drain the outer caliper and then the inner. Why not the inner first because that is where the fluid source initiates it's entry into a caliper, i.e., line to inner caliper, line to between inner and outer caliper. Wouldn't it be logical to first drain inner so fluid is fresh in the inner chamber and then to drain the outer?

Radiator and A/C Heat exchanger clean-out:

Now I know what remover card is... I remember when I purchased the car, I could not for the life of me figure out what this plastic useless credit card was meant for. Now I know it's for the fog lamp housing removal. I used a credit card and it worked...

The removal of the bumper is much easier than I thought, especially after repeating the removal twice because I forgot to plug the 'ambient temperature sensor connector' and I guess I didn't plug the side marker in all the way. Note of caution: be very careful when removing the connector and disconnecting the harness on the passenger side that links the bumper electrical. I snapped the locking connector and the tolerances are very tight so you have to cable tie it together. (electrical tape was not enough tension)


On Sunday, one of neighbors asked if someone stole my wheel on Saturday night!


You can see the connector for the Ambient Temperature Probe that I forgot to connect in the lower right hand corner...

The red bucket is for scale.


The driver side. I don't know why but the driver side was much dirtier than the passenger side. this images are after vacuuming but not before the water spray. Definitely a cure for OCD.


You can see the salt tally on the fan housing. If you don't know, we salt our roads here in Michigan so if a surface is not treated, it will corrode. In this case it was mild surface accumulation, not brown rust.

Spark Plugs:

I read and re-read the articles on spark plug change. I can't remove the muffler because the bolts that clamps the connector between the muffler and exhaust manifold is completely rusted.



Believe it or not, this is the only corrosion of fasteners on the car. (both sides) I'm going to grind the nuts and replace the faster: bolt, nut, washer combination. Anyone know the size?

Are there any material scientists out there? If I were to grind this off and replace with a corrosion resistant fastener, which material should I use? I'm thinking of using a screw made from SS 300 that meets QQ-P-35 and meet FF-S-86 standards. Then again this material has to resist very high temp and stress from expansion of pipes.

I'm also curious if anyone in California could check to see if there's is corroded?

Ok, even if I could remove the bolts, how would you completely remove the muffler? If you see in this image, the bolt which loosened would lift up but it cannot due to interference from the body.


there is no room to remove the coils because of the muffler mount.

A view from the bottom:


I"m wondering if anyone else has this working limitation.

Last question: when the car ran without the ambient temp sensor attached, it faulted so now i have a 'visit Engine Center' on my start-up dash, error 17 = intermittent Amb Temp... How long before this disappears?

Update: it disappeared this morning = 12 hours later.


Edited by racerken
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PS fluid: the small cap covers the blowoff/relief valve.

brake bleed: yes, technically bleed inner then outer, but in the whole scheme of things, you're not going to get every last little itty bit of particle/old fluid out so it's not that imperative.

mufflers: yes, those bolts are "upside down" much to the annoyance of many DIY'ers. for the first time removal, you have to take off the whole mounting bracket (have to go from behind to unbolt it. then, after you remove the stablizer bar that runs to bumper the cans should be able to come out with a little twisting and rotating. it's like a puzzle. and before re-install, simply reverse those "upside down" bracket bolts so that the bolt comes out the bottom for easier removal next time.

sparks: i have not tried them yet (or the mufflers above) but i have researched enough to know that you dont need to take them off to change sparks. yes, it makes it a little easier but not imperative. i have seen DIY's done both ways.

temperature dash error: some things seem to clear themselves, others require a durametric (or PIWIS / $ at your local shop). i'd say that if youre sure the temp is working again and all connections are secure BUT the light wont clear, then it's probably not self clearing.

good luck.

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Thanks, Spiffy!

I'm going to tackle the muffler removal after I receive the new fasteners. I checked with some material engineers and they did mention that the worst condition is salt + heat so it's a no win situation. I guess I just have to replace all to-be-corroded fasteners prior to siezure.

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sure! i live in the mid-atlantic (MD suburbs) and we have humidity, rain, some snow, etc but thank goodness i have a second vehicle so that the 997 rarely sees moisture. i do notice some bolts rusting a bit but it's no comparison to where you are!

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No need to remove the muffler for the spark plugs, you just need the right tools, It is off course easier without, and it will be a bit of torture

Below is the extract from the Porsche Manual, I bought a spark plug wrench with an integrated cardan shaft at Autozone, it needs to be in 3/8 and you need a 3/8 extension too, there is little space in there, you will understand when you will start

Also, I did change the spark plugs at half the advised KM ( 45 000 KM) just to be sure, there were really looking good, like new...and there was absolutely no difference in fuel efficiency or engine running at idle, ask yourself if you really need to do that? the Porsche Bosch 4 electrodes are there to last 4 times longer than before and it does work well

I would avoid taking off the muffler, this is absolutely unnecessary unless you want to change them, I did it myself to reweld them as there was a vibration at high RPM due to a broken metal strap that maintains the pipe together on the PSE..., The exhaust holder pins have a high chance to break when you will try to unscrew them, and believe me I used a lot of WD 40, each holder is 350 USD, + new screws, + 2 new sleeves as they need replacement all the time it can be a 1000 bucks, the socket wrench with cardan shaft is 5 bucks...

Good luck

Removing spark plugs

Shield for ignition coils

1. Remove the 2 M6 x 20 fastening screws -arrows- for the shields on both cylinder heads and remove

the plates.

2. Unplug cable plug for the ignition coils. To do this, slide the rubber grommets upward first. Press

locking tabs on the respective ignition coil and pull off the individual plugs. In the interest of better

accessibility, unplug the cable plugs for the solenoid hydraulic valves.

Screws for ignition coils

Loosen two M6 x 25 fastening screws -arrows- each per ignition coil and remove the 6 ignition

coils individually.


Incorrect tool for changing the spark plugs!

· Ceramic body breaks!

Ä Only use the approved tool spark plug socket wrench NR.14 and 3/8" extension, 16° moveable NR.15.

4. Unscrew the spark plugs using the tool spark plug socket wrench NR.14 with 3/8" extension, 16°

movable NR.15.

top of page


Installing spark plugs


Incorrect tool for changing the spark plugs!

· Ceramic body breaks!

Ä Only use the approved tool spark plug socket wrench NR.14 and 3/8" extension, 16° moveable NR.15.

1. Install spark plug with spark plug socket wrench NR.14 and 3/8" extension, 16° movable

NR.15. Ä Tightening torque: 22 ftlb. If the spark plugs will be removed and installed again for

another activity, the tightening torque is reduced. Ä Tightening torque: 19 ftlb.

2. Insert ignition coils in the spark-plug recesses and tighten using two M6 x 25 fastening screws each.

Ä Tightening torque: 7.5 ftlb. . Then connect the cable plug and position the rubber grommet on

the coils.

3. Insert the shield again and fit using two fastening screws. Ä Tightening torque: 7.5 ftlb.

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  • 3 weeks later...

On my 996 it's a lot easier to get at stuff with the rear end removed and then remove the exhaust shields. It's really easy to get these bits off. I assume the 997 would be much the same. When removing the rear end look out for the screw that is just inside the wheel arch where the cowling meets the main body. You will need to apply a cross head driver vertically upwards to get at it. The other screws are obvious.


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HI Brendel, thanks for the tips. I was wondering if you could expand on what NR tools are. I also discovered a crack in the coil housing... not good i guess.

I rightly or wrongly assumed as it was instructions from Porsche themselves to their mechanics that NR means 'number' as all Porsche tools have a number to identify them. No help unless you can reference them I know, but it gives you a clue at least!

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I don't believe that the special tools are necessary, but If you want I will send you the pictures ( I am in the office right now... :renntech: )

The socket is standard,

The socked insert, is strange, I guess it is acting like a small extension to put on the plug side as the plug tubes are long and you don't have the space to insert a long socket in one go as you have the muffler holders on the other side

The extension bar is special, it has a barrel connection, instead of a square one, I guess it is to avoid the usage of a cardan and therefore gain space and be able to have the right torque numbers on the plug

My solution to this was to buy a socket with a cardan in 3/8, I bought one at autozone last time I was in the US, but I never tried it, from experience I know it would work though ( you need a dyno wrench on 3/8 also...) the role of the cardan is that it folds and therefore allows you to put a rather long socket in the plug tube

Before that I also did it with a normal 1/2 tool box, I had to put the socket in the tube first, connnect the cardan, and then connect the extension bar, the reverse way is more tricky you need to hold the socket with a thin piece of metal once you are done and then extract it somehow, magnet..., not an easy thing

If you are properly equiped you should be able to use your dyno socket wrench with the cardan being straight, don't use a torque wrench or tighten plugs with a floded cardan

On some plugs I could not use the torque wrench, I therefore applied basic mechanic knowledge and everything worked perfectly


Regarding your cracked coil, I drove with one like that too for 2 years before changing it, I ulitmately changed it when I did the plugs, but there was no change at all on how the engine behaved, I also did not have any misfiring

by the way your pictures motivated me to take the front bumper and clean the radiators, I did it with a high pressure hose, it is amazing what comes out of it, It is a very easy procedure in the end, it took me a good 2 hours, but I am sure if I had to do it again 1 hour would be enough

Good luck with the plugs

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  • 3 months later...

OK, I decided to conquer the spark plugs this weekend at 38k miles. I wanted to have access so I removed the mufflers because I could not figure out how anyone with normal hands could get in there, let alone see what's going on. Rear Fascia removal, rear quarter panel removal, rear + left + right heat shield removal. I grinded off the nuts/bolts that held the exhaust to collector union (the ones that are completely rusted in the above pictures.

Problem 1: I have the Sport Exhaust so there is a vacuum actuator with 3 bolts + nuts connected it to the muffler assembly. Well, I sheared 2 out of 3 off on one side. I should have soaked in penetration oil overnight.... I hope the unit is not costly. I noticed that the hose clamps on both units were also rusted away but the hose is in good condition.


close up


The Muffler came right off after removing 3 nuts that mount the muffle assembly onto a bracket that fixes the assembly to the engine.

Heat shield between engine and exhaust also was removed.

(2 hours)

The removal of the coils and plugs took another 2 hours of careful surgery. Plugs 1-2-3 came out fine. Plugs 5-6 also came out fine. Plug 4 took a trip to the store to purchase the 'master series Torx 40' head which is short enough to attach to the top coil bolt + the ratchet without interference with the exhaust mount.

Problem 2: Coil on cylinder 1 has a cracked housing and I have a replacement from Sunset. It has a significant crack in the plastic housing and the resistance reads .8 Ohms which is identical to the new unit but I'm replacing anyway.

Little cracking on the sided:


Huge split!


It just appears to be heat damage to the plastic but no affect on the performance. I guess my thought is that I don't want to be on the side of the road, especially on a part that takes hours to replace. Interesting, cylinders 4-5-6 have no cracking. 1 is pretty bad, 2 and 3 are very minor so I'll go another 40k miles.

Anyway, assembly takes place tomorrow.

Edited by racerken
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Loren, I have a question about the exhaust manifold bolts. While I have everything off (mufflers, catalytic) I'm removing all the rusted nuts/bolts. should I attempt to replace the exhaust bolts before they are too far gone? Or, just leave them alone in case I should shear it off...

Please take a look at these pictures.


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I have to complain about this because I'm in so much mental stress. I was attaching my Catalytic Converter to the exhaust flange and was torquing the fasteners when the torque wrench I was using malfunctioned and I stripped the threads. I now have to buy another bolt/nut from the dealer and grind the bolt/nut... never ending.

My first 'good' torque wrench was a click-stop from Sears and it lasted 20 years before breaking.

My replacement was a 1/2" Wright Tool unit at $150. A charm.

My first 3/8" torque wrench was a Tekton at $40 about a year ago. I bought it because the store swore by them.

The Cheap Tekton just failed. One would think that failure would be under torque but over torque killed me.

Lesson of the day: just buy the expensive one all the time.

Does anyone else just take their time and work on cars for weeks at a time? Remember, I travel weeks at a time as well so I figure that if I'm out of town who cares if my car is in pieces...

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Wow, check out that exhaust hardware in racerken's pictures at the beginning of the thread. That is what happens when you use plain steel hardware on a stainless steel part. Plain steel and stainless are at opposite ends of the galvanic chart. I can't believe Porsche did that! Everyone should check out their exhaust hardware and anything that is rusting should be changed over to 18-8 (T304) hardware as soon as possible. Even if you do not live in the rust belt. Just above notice the cap screws fastening the exhaust header. They are rusting at about the same rate as the header. That is because both are stainless. Both could also be plain steel. Stainless rusts, just at a slower rate than plain steel. The cap screws on the headers should be replaced probably about every five years because they are subject to stress corrosion cracking. Because the cap screw is under tension, at points of surface corrosion a stress raiser develops initiating a crack. A little torque and the head snaps right off. Big headache. Others in our group have reported broken cap screws. It is so common that Pelican Parts sells a broken exhaust bolt removal jig for...$325. Much cheaper to replace the cap screws now and again.

Edited by Mijostyn
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Racerken, I was checking out Porsche's exhaust repair procedures. Porsche insists that you replace the clamping sleeves between the cans and the cats EVERY time you remove them. They are not reusable. That is why they are using the crappy hardware. This is a pain because in order to replace the sleeves you have to remove either the cans or the cats. At this point I would just leave them alone.

When the hardware rots off you can replace them. If you do replace your exhaust manifold hardware do it one bolt at a time starting with the center 4 ending with the two at the ends. Make sure you check a few times for leaks.

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Hi Mijostyn,

Thanks for all of your feedback which serves as a sanity check. In otherwords, I'm not insane from starting a simple plug change to a major corroded fastener replacement project. My car is back together now and in case anyone wonders, yes, new spark plugs after 40k miles DO make a difference.

I basically had to purchase two new tools:

A disc grinder x 25k rpm.

A 1/4" drive die grinder x 20k rpm.

both came from HB Frt so it was not so hard on the pocket book.

The 1/4" tool was purchased from a reputable machine tool shop so if anything, the cutting head was the most expensive item at $45.

Make sure you wear a full face mask because I allowed the 1/4" grinder to deflect and the tool hit a flange whereby the impact sheared the tool shaft which sent the bit flying like a 50 caliber bullet.

It takes about 3 minutes a nut to grind off.

My theory is that Porsche uses soft metal so it's easy to grind off.

The cost for each exhaust flange bolt nut combination:

Exhaust manifold to catalytic converter fasteners and gasket.

# 42 x 6 bolts $1.98 each

# 8 x 6 nuts $2.60 each

#7 x 2 gasket $4.96 each

the # refers to the standard porsche parts exhaust diagram which I found somewhere in this site.

If you do live in an area which utilized Salt during the winter such as Michigan, I highly recommend budgeting at least $75 for nuts/bolts (if purchased from Porsche) to replace all corroded fasteners because if you allow them to corrode beyond service, you'll be grinding. I went 4 years on these bolts and i drive everyday in the winter. I pity you folks that garage a fine car during the winter - you're missing the best slide experience.

If you have PSE, your hose clamps will also need replacement as they half were completely corroded.

Also not cheap:

Hose Clamp x 4 $4.22 each (2 at each vacuum actuator 100% corroded) (2 each from the steel braided hose to plastic hose transition - just above the plugs 50% corroded)

Clips that fasten the hose to the frame x 2 $0.25 each

My exhaust manifold bolts will continue the path of corrosion until either the manifold drops or I pull the engine out for rebuild - at the rate I drive will be another 8 years?

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Racerken, what did you do with those clamping sleeves?? Since once you loosen them they are trash I would just use a cutting wheel on a rotary tool such as a high powered Dremel cordless and cut through one tab on either side releasing the sleeve. I am concidering putting a Fabspeed exhaust system in so, I may get a pass at it soon.

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I grinded the stud and nuts then the sleeve loosened up. Once the sleeves were out I hit the remaining stud with a hammer. No issues. On assembly I used Porsche bolt and nut which was an m8 x 1.25 x 40mm bolt and the flanged locking nut. The sleeve is completely reusable.

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racerken, I just got back from my Porsche dealer having blown wheel bearing #3!! This time they are replacing the bearing, the knuckle and the hub. Pretty soon I'll have a new car. Anyway, I talked to my favorite tech about the clamping sleeves. Porsche does not want them reused after they are loosened. Their argument is that the heat stretches them over time and once they are loosened they may not seal again correctly causing an exhaust leak. So, his advice was to shell out for new sleeves, ditch the hardware and use SS. I'm seriously considering either Fabspeed or AWE exhausts so, I figure I'll just live with the crappy hardware until then.

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