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Cayenne 3.6 V6 Intake Manifold Removal DIY

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Well, I joined the party... I've tried to replace the membrane as well without success.  I couldn't get to the last triple square, and maybe somewhat stripped the middle one. I may attempt it again with moving the coolant hoses..  If not, I'll be taking it to the dealership for the valve cover install.   I have no codes, but the whistling seems to be getting worse.  I like the 957, but this job is a pain for sure, gone are the days of Autozone 10.00 PCV valve pulled from the top of valve cover, 2 min install.. 

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Here is a follow-up and a few learnings from that job. First, never use electric tape to temporarily fix the crankcase  breather hose while waiting for a new one to arrive...tape melted and I got a huge vacuum leak on my way to work. Duct tape is the way to go 👍

Secondly, despite replacing my PCV valve which I knew was bad, the CEL came back with the dreaded P12A2 code. Now, to think I did all that work for nothing was a bit upsetting to say the least. I ordered a new fuel pressure sensor that I have not installed yet. Meanwhile, I checked my fuel tank cap and noticed it did not close tight, because the o-ring seal was all shrunk and cracked. Knowing this too can cause a P12A2 code, I swapped with the gas cap from my 911, just to try. I cleared the CEL code and went to work with the Cayenne. And bingo! The CEL light did not turn in on my way back as it usually does. So, before taking off your intake to change your valve cover, check you gas cap first would be my advice 😎.


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

Had to put this on back burner due to work, but I'm attacking it today. I can't seem to get the intake and injectors lined up. I have the injectors loosely installed and I'm trying to position the intake between it and the block. Any pointers? How did everyone do this? Thx 

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  • 2 months later...

I just finished this about an hour ago, and it was the hardest repair I've ever done.   This guide and a video on YouTube from Ptehch really helped with getting everything off.  Passenger side was kind of easy - use penetrating oil for the parts that are stuck.  Everything on the drivers side basically sucked.

- Removing the water hose (t25) - I just shoved the hoses down and pushed on the electrical harness to force the bit in

- Lower M10s - I used a crow bar to get move the metal part down and then got the socket in

- Fuel rail - to be honest, I didn't remove this properly.  I just kept wiggling the manifold and eventually it all came off (may have caused some of my problems later on)


Reassembly sucked as well.  that gas line in the back is the worst.  Why would they even design it that way??  It's like they hate their mechanics.  I tried lining up the gas line ahead for both the upper fitting- which wouldn't line up again when assembled then the lower fitting and it kind of worked except I couldn't tighten it enough- had gas shooting everywhere.  Since I had it kind of together at that point,  I ended up taking off the filter (or pump?) - its the part that connects to all the other gas lines.  I took off the 3 screws and the upper gas line.  Once that is out of the way there is enough space if you have a short 14 wrench.  I had to cut on in half to get it in there to tighten everything.  I think if I ever have to do that again I would take that out at the beginning.  If you look closely at the Ptech video, he has it out.  


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  • 4 weeks later...

For those having trouble locating the third M10, it's there, even on the newer engines (mine is a 2013) but it's completely obscured by the water pipe. The middle bolt is also unable to be pulled until the water pipe is moved out of the way. 


I found it necessary to remove the positive cables on the driver side of the engine to get enough room. I'm still working on this but I just need to get the extended T30 and I should have this off. 


For anyone considering doing this, give it to a mechanic if you can afford it. I'd have stopped 2 hours in if my mechanic wasn't out of town for two weeks. I've been doing an engine out overhaul on my 964 911 for the last two weeks so I figured I'd tackle this myself. How hard could it be? In short, it's an awful job. This engine is designed by somehow who put zero thought in being able to work on the car. Many of the bolts required contorting myself or various lines to just barely manage to get it out. I have no idea how I'm getting it back in. 


For reference, here's the two M10 on the back of the engine. The top one I thought was the target, it's not. It's the bottom one you need to remove. 



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  • 9 months later...

JUST completed this to fix my torn PCV. Took my DIY skills to the next level for sure... got some good tips here to remove that T25 screw inserted vertically.

Car starts up great. First test tomorrow! Thanks for this awesome and detailed DIY tutorial!!

Sent from my SM-G950W using Tapatalk

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  • 1 month later...

I appreciate the detailed procedure, but before I embark on this apparently fiddly project I hope someone out there could address a few questions regarding my 2009 Cayenne 3.6 did with 120k miles.


I am getting a P0674 code from Durametric-which suggests the pressure sensor is supplying an implausible high value.  There are no problems with startup, rough idle, loss of power, etc.  Just that annoying CEL.  There seems to be a fair amount of conflicting interpretations of the P0674 on the web, and the absence of symptoms is puzzling


Why/how would a failing pcv valve cause this (BTW, I had the manifold professionally replaced 14 months ago)?  The old hand over the oil filler procedure doesn't suggest it is the pcv.


How likely is it to be a bad high pressure sensor (had that replaced too)?   Am I correct that the same procedures are required to access that?  Anyone know the electrical characteristics of the sensor or if it reads high when it fails?


Could it be a fault in the high pressure fuel pump-particularly the internal  pressure relief device (yep, replaced the pump WYIT preventatively 14 months ago, too)?  Refitting a new pump would be an easier DIY fix, but an expensive part to throw at the problem.


Any advice would be welcome-thanks in advance.




So, replaced the sensor, it is actually accessible without removing the manifold.  Hardest part is unclipping the electrical connector.   Cleared codes, returned after about 25 miles. 


Replced HP fuel pump with new Hitachi pump.  Procedure is different from the v8 diy posts, pump shaft is perpendicular to the camshaft and apparently driven by a lobe rather than inline with the camshaft via the clutch described for the v8s. Good news is you don't need the $70 plastic plug with this application.  Close quarters, as with all P-car repairs, but not too difficult, need some stubby metric wrenches for fuel lines and long reach torx T-27 socket for the 3 screws holding the pump.  Took maybe 2 hours start to finish.  Starts and runs great, but unfortunately CEL returns.


At the end of ideas as to how to address this problem.  Any suggestions?

Edited by cgmillard@cableone.net
Additional follow up info.
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Once the car warms up, youll hear a whistling noise if its the pcv valve sounds like a bearing going when it gets bad ebough. But once warmed up after 20-30 mibutes of driving I would notice that at a stop light the car would idle at 800 and fluctuate up to 1200 and just flutter between those rpm's. Normal driving was fine. theres also a hole near where the PCV valve is on the valve cover that you can put your finger over and if you feel air/vacuum... its time to replace.

Sent from my SM-G950W using Tapatalk

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  • 3 months later...

Very nice tutorial. I'm just about to replace the vacuum line and I believe I have to remove the intake manifold. 

1. Is it really necessary to remove the whole manifold in order to do it? 

2. If so, after removing the manifold, are there more disassembling parts? 


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  • 2 months later...

Since I’ve benefited from this detailed DIY, I’d like to contribute some pointers I’ve discovered along the way. 

I have to remove the intake manifold to fix a leaking valve cover. Bad job by an Indy 50k kms ago. Didn’t want to bother until it started to drip on the floor. Thought I have this fixed with the constant lockdowns. While the intake was off, I noticed issues which I have rectified along the way. 

1. Disintegrated conduits and brittle harness. Both injectors and coil packs. 

2. overdue spark plugs change. 120k since last change. My bad. 

3. intake valve baked oil/carbon build-up. Installed an oil catch can. Placed the can behind the right headlights. To be permanently fixed - light methanol water injection kit. Doesn’t seem to be an easy way to walnut blast these VR6. 

4. cracked auxilary water pump. Not a surprise as the hose Y joint and the plastic inlet to engine has cracked 2 years ago. 

The steps in the DIY was spot on. Didn’t have to change the vacuum hose as it was changed 30k kms ago. Injector seals are intact - no leaks after reinstalling. One thing that made it easier to remove and reinstall the fuel line is to remove the high pressure pump. 3x torx 30 screws and remove the in and out lines. A size 14 and 16 can have the nuts removed with decent space. With the pump out of the way, you will have some decent space to disconnect the lower fuel line  nuts. I remove the entire short fuel line connecting the lower fuel rail to the upper. Makes the process much easier when removing and reinstalling. It’s enough to have to juggle between to screwing up the upper injector harness and somehow correctly slotting in the lower intake manifold with the fuel rail attached to the injectors. The caveat? You may have to change that o-ring on the fuel pump. I didn’t and hasn’t seen a leak yet. 


I hope this helps. I’d also high temp sprayed the fugly grey color on the intake manifold to matte black while it was out. Now it looks slightly like a decent engine bay. Next tasks, flush pdcc, replace reservoir, replace cardan shaft and fixed the rear doors lock actuators. 

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