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I recently just picked up an '08 Cayenne GTS from a fellow Rennlister and have been doing a ton of reading about the CGTS. My question is, are the coolant lines on the 08 CGTS plastic or aluminum? If plastic, I want to plan to replace them soon, as the vehicle has 108k on the clock. I've read numerous articles and it seems some state that they don't have this issue and are aluminum and other articles that say they are plastic. I'd like a answer from the guys that actually own one of these, or what's the best way to see for myself? I plan to keep this vehicle for quite some time, so it'll be nice to keep her in tip top shape. Thanks for the help!
Only way to know for sure is to look for yourself. There are high quality endoscopes that can be bought for $40 now. As i recall it seems only the very early cars had the plastic pipe. This hasn't nearly been an issues on the 2008-2010 like it was one the first gens.
957 generation replaced the plastic lines with aluminum ones, but I believe there is still a junction that is plastic and a glued in fitting in the back of the motor that could still be an issue. Someone more knowledgeable will chime in with a more definitive answer though.
First off, they are plastic. Unless everything I have read is wrong, Porsche never put aluminum pipes under the intake from the factory.
However, the pipe in the 957 (08 - 10) is a redesign. After the issues with the 955, they put in a different setup. As was noted, the 957 does not suffer the same 'blown pipes' issue as the 955.
The 957 does have a potential issue with the joint at the back of the motor. that, as was noted, is glued in. They can fail. The dealer will tell you the motor needs to come out to fix it, but it can be repaired (JB Weld) or replaced without, if you are willing to reach into tight spaces. Unlike the pipes in the 955 that will fail at some point, the 957 issue is a "May fail" problem.
So what I'm gathering from these several replies is that the pipes are plastic, and that they may fail. Is there any reason to replace them with the aluminum pipes?
As for this joint at the back of the motor, is this accessible from the top or from under the truck? Is the new part from Porsche a redesign, or is it still the same part that I'd be replacing and is it worth replacing? I want to keep this truck, so I'm willing to do what it takes to keep her running beautifully!
Unlike the pipes in the 955 that will fail at some point, the 957 issue is a "May fail" problem.
A "May Fail" problem would then apply to absolutely anything on the vehicle; whether it be mechanical, electrical or any typical static non-functional component. ;-)
To date, there have been no known failures of the coolant pipes on the 957. Communication between many owners & key service personnel at dealerships have confirmed this.
So what I'm gathering from these several replies is that the pipes are plastic, and that they may fail. Is there any reason to replace them with the aluminum pipes?
As for this joint at the back of the motor, is this accessible from the top or from under the truck? Is the new part from Porsche a redesign, or is it still the same part that I'd be replacing and is it worth replacing? I want to keep this truck, so I'm willing to do what it takes to keep her running beautifully!
-Andy
Not quite. The plastic pipe under the manifold is not known to fail.
The connection at the back (called the 'coolant manifold') is known to fail. But when I called it a "may fail" part, I meant that in contrast to the pipes under the manifold on a 955 (or an IMS bearing on a 996). The 955 pipes are going to fail at some point. The water manifold connection has a history of failing on numerous cars. But not all.
There is a replacement that is not a glued joint (factory part).
Your GTS has a plastic pipe from the thermostat to the coolant bridge, at the rear of the engine. BUT this is not prone to failure like the pipes in the 04-06 engines.
If this is bothersome and you plan on changing it then add the water pump and thermostat to the list and check the fitting on the water bridge. That fitting is glued in place and has failed unexpectedly.
All coolant is lost rather suddenly.
So what I'm gathering from these several replies is that the pipes are plastic, and that they may fail. Is there any reason to replace them with the aluminum pipes?
You gathered wrong. The pipes under the manifold are plastic. They are a different design from the ones that failed on the 2003-2006 4.5L V8. You have a 4.8L V8. They don't fail and there are NO aluminum ones available to replace them with. So "forgeddaboutit.."
Originally Posted by simpsoap
As for this joint at the back of the motor, is this accessible from the top or from under the truck? Is the new part from Porsche a redesign, or is it still the same part that I'd be replacing and is it worth replacing? I want to keep this truck, so I'm willing to do what it takes to keep her running beautifully!
Porsche redesigned the entire coolant bridge that connects the back of the cylinder blocks. That bridge is where the glued in pipe is. I believe Porsche claims engine-out is required to replace the bridge with the new design (where the pipe is screwed in.)
Some people have reglued the pipe using a better epoxy, some people have threaded the hole in the coolant manifold and found a screw in fitting for it, and some people added a retainer that keeps the pipe from popping out even if the glue fails, and finally some people have added a set screw to the junction that keeps it in place. It is NOT at all easy to get to - or even to see since it's buried under the high-pressure fuel pump.
Thing is - it doesn't fail that often. If the engine is out for some reason - that's a good time to address the problem using one of the techniques above - or simply do what Porsche would do - replace the entire bridge.. The parts aren't that expensive (less than $300).. https://www.porschepartsmerriam.com/...ld-94810606121 (and you can see a nice picture of the manifold). Porsche does call for engine-out to replace it - but - I had one replaced by Porsche on a 2006 CS - and they didn't remove the engine to do it. It might be different since the 4.8L engine has direct injection - and the high-pressure-fuel-pump is right above it.
The other pipes that are of some concern are the two going into the thermostat housing at the front of the engine - these are aluminum epoxied into aluminum. Bit of a PITA to get to - since the water pump has to be removed and the intake manifold has to be removed - but it can be replaced with the engine in.
The thermo housing is in the green box. The two front pipes on it are glued (duh!) in. (borrowed image from another thread..)
Originally Posted by simpsoap
-Andy
Good luck with this... try not to obsess..
Last edited by deilenberger; 05-12-2018 at 04:27 PM.
After all the posts here, I'm going to just relax and enjoy the truck. You guys have given me piece of mind that the truck is fairly robust and that the lines won't fail, and that this manifold at the back of the engine isn't very likely to fail either. This is why I love this place, thanks for the assistance fellas.
After all the posts here, I'm going to just relax and enjoy the truck. You guys have given me piece of mind that the truck is fairly robust and that the lines won't fail, and that this manifold at the back of the engine isn't very likely to fail either. This is why I love this place, thanks for the assistance fellas.
Next up, replace the horns.............
-Andy
I have the OEM horns from my 28,000 mile 09 TTS if you're looking for OEM. I replaced them with a Marco Hurricane and Tornado (3 different tones) but they are air horns with integrated compressors so require wiring with heavier gauge wire and a relay using the OEM horn wires only as a trigger for the relay.
05-10-2018, 11:55 PM
2008 Cayenne GTS coolant line question
