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My 2011 S with 83K miles on it had a failure of the glue (Loctite 638/648) that holds an aluminum coolant pipe into the thermostat housing on the front of the engine. As a result I lost an unknown amount of coolant and the engine temperature rose. I would not be surprised if we start to see more of these failures as our cars age and the glue is exposed to more and more heat cycles.
The reason for this failure was the failing of the glue. Porsche had the exact same problem on GT2/3s and there was an NHTSA investigation. At the end of the investigation, Porsche convinced the NHTSA that there were no safety issues with this failure. The link below at the NHTSA will download a very interesting doc on this. One nugget in here is that 2011-2014 Cayennes and 2010-2014 Panameras used the same glue.
Porsche says that they introduced a glue application metering system to make sure the fittings received the correct amount of glue in 2008 implying that the failures were due to not enough glue being used. Obviously this is not the case.
Also Porsche mentions that there isnt a safety issue because in the GT2/3s the coolant comes out behind the rear wheels - this is obviously not the case for Cayennes and Panameras.
Anyway, if anyone here has had this failure, please post in this thread. If there is enough evidence that this is a big issue, maybe we can get the NHTSA to take a look. One idea would be to build a list of all the failures for all cars that have had this failure - across all Porsche models.
BTW, Porsche has a "fix" for this issue that uses threads instead of glue. Go figure. The cost is $1,800 to have a dealer implement the fix. Ask me how I know.
Last edited by deilenberger; 07-28-2018 at 12:18 AM.
Reason: Added engine to the title
Not all generation 958 use that style tstat housing. Mine being one of them luckily. All three of the pipes that come off of it are fastened in with o-ring seals. Which to replace you’ll have to a gasket place to match them since there is no PET on them.
Thanks Trendy. The Dealer is implementing the fix for me so I should receive a parts list on the receipt. I'll share the list when I get it. In the NHTSA report on this Porsche said that the years 2011-2014 are affected. Not sure if this is true or not.
Wow, thanks for the legwork, SJG, and sorry about your $1,800 bill! It seems I find more and more comfort in getting a CPO '14 S last month almost every time I look at this forum!
So it appears that the Thermostat housing was upgraded from part # 94810608000 to part # 94810608002.
I believe that these two pics (new part is 1st) represent the two types of housings. Notice a difference?
New owner of a 2013 Cayenne GTS.
PO didn't have much in the way of records (2nd owner. car only has 38K miles) so I brought it to the dealer to have a baseline done. (oil/ brake fluid flush and general look over)
Got a call that the "thermostat pipe" could be moved by hand and should be replaced NOW.
Service advisor thought it was around $2800. to do. I'm hoping it's not the California Porsche tax and comes in closer to the $2K mark.
Told him to use JB weld but got nowhere with that. Should get the car back Monday.
Tony
Looks like I have this to look forward to on mine, as well.
Not the best photo, but shows most of what I could see with a light looking at the housing with everything in place. No movement from the pipes, but I also didn't try too hard.
I suppose the question is, do I make an attempt to add something externally to hopefully get it to last that little bit longer and change it out when it's not freezing outside, or just order the new housing and replace it as soon as possible to prevent being stranded due to coolant loss.
I suppose the question is, do I make an attempt to add something externally to hopefully get it to last that little bit longer and change it out when it's not freezing outside, or just order the new housing and replace it as soon as possible to prevent being stranded due to coolant loss.
Not all of these fail. The frequency of failure appears (so far) to be WAY less than the failing coolant pipes on the 955 V8's. So far I've only heard of perhaps 2-3. It can look like more on the Interwebz due to people posting the same incident in multiple threads, and on multiple forums. IF I was replacing my water pump - meaning the system was drained - I might consider R&R of the thermostat housing. It does involve removing the intake manifold and the injection rail. It might be possible to do by lifting the intake manifold up at the front - but looking at the AllData instructions - they do call for R&R. They give a cost basis of $425 for the housiing, and 6 hours labor. I would imagine it might be wise to replace the actual thermostat element at the same time ($220) since the same labor is involved in just replacing it if it failed later, and that would give you all new seals/parts in the housing.
Not all of these fail. The frequency of failure appears (so far) to be WAY less than the failing coolant pipes on the 955 V8's. So far I've only heard of perhaps 2-3. It can look like more on the Interwebz due to people posting the same incident in multiple threads, and on multiple forums. IF I was replacing my water pump - meaning the system was drained - I might consider R&R of the thermostat housing. It does involve removing the intake manifold and the injection rail. It might be possible to do by lifting the intake manifold up at the front - but looking at the AllData instructions - they do call for R&R. They give a cost basis of $425 for the housiing, and 6 hours labor. I would imagine it might be wise to replace the actual thermostat element at the same time ($220) since the same labor is involved in just replacing it if it failed later, and that would give you all new seals/parts in the housing.
Right, things can seem worse on the internet, because generally these topics turn into an echo chamber of people that have experienced the failures. My usual experience is that if it can go wrong, for me, it will (laughter, trailing off to sadness) Generally, if it's a possibility to fail, I'd feel more comfortable eliminating that possibility. I was intending to replace my water pump come spring regardless, adding this will just increase the bill, and a bit of my time. I was finding the housing for $310 here, and the thermostat itself for about $200. Roughly $700 (including water pump) to not potentially be on the side of the road and listening to more broken Cayenne ridicule would be worth it IMO.
My paranoia may still lead to me spreading some JB weld around the exterior, just to make sure it holds until I do the water pump and everything else this spring. If nothing else, it'll at least make me feel better.
My paranoia may still lead to me spreading some JB weld around the exterior, just to make sure it holds until I do the water pump and everything else this spring. If nothing else, it'll at least make me feel better.
JB Weld is pretty amazing stuff. BMW had a service campaign for the early 318i engines - which were prone to massive coolant loss when part of the head eroded away where it passed into the engine block. It used an O ring as a seal - when the head eroded - the O ring blew out and blewie.. BMW's fix for this was to remove the head, remove any corrosion with a Dremel tool, then build it back up with JB Weld - and using the same Dremel tool, shape it to take the O-ring again. Funny thing is - the fix lasted longer than the original design. I used it a lot on the cooling systems of later BMW engines where they made plastic bits that would just spontaneously start to leak. I had a plastic thermostat housing on a E39 528i that started leaking right out of the center of the plastic casting. No crack, no sign of any damage - it simply became porous. A nice coating of JBWeld on the plastic after a bit of prep - and it was still on the car when I sold it about 30,000 miles later. Count me as a fan.
In this case I don't think it would be necessary to put an entire bead around each pipe (although that would be nice - but harder to do) - I think some strategically placed globs between the pipe and the housing would secure it in place, and then just rely on the original glue to keep the coolant in. If you do it - I'd love to see photos of it..
Completely agree that there do not seem to be too many of these failures reported as of yet - although I'm sure many go unreported. From what I understand, the pressure inside the coolant pipes is rather low (like 15 psi). One theory I've seen for the the failure is that the pressure release valve in the coolent overflow cap does not work properly and as a result the pressure rises and the the glue comes undone. Still seems like an unnecessary risk to me. I guess using glue allowed Porsche to reduce the number of bolts (and a little weight) in the car and simplify assembly.
I do suspect that we will see many more failures as the cars age and the glue weakens due to temperature cycling etc. My failure happened at altitude in the the mountains where relative pressures change and the outside temperature swings are much greater than the car normally experiences. Unfortunately I was far from home else I would have taken on fixing it myself.
JB Weld is pretty amazing stuff. BMW had a service campaign for the early 318i engines - which were prone to massive coolant loss when part of the head eroded away where it passed into the engine block. It used an O ring as a seal - when the head eroded - the O ring blew out and blewie.. BMW's fix for this was to remove the head, remove any corrosion with a Dremel tool, then build it back up with JB Weld - and using the same Dremel tool, shape it to take the O-ring again. Funny thing is - the fix lasted longer than the original design. I used it a lot on the cooling systems of later BMW engines where they made plastic bits that would just spontaneously start to leak. I had a plastic thermostat housing on a E39 528i that started leaking right out of the center of the plastic casting. No crack, no sign of any damage - it simply became porous. A nice coating of JBWeld on the plastic after a bit of prep - and it was still on the car when I sold it about 30,000 miles later. Count me as a fan.
In this case I don't think it would be necessary to put an entire bead around each pipe (although that would be nice - but harder to do) - I think some strategically placed globs between the pipe and the housing would secure it in place, and then just rely on the original glue to keep the coolant in. If you do it - I'd love to see photos of it..
I had never heard about that BMW service campaign. Kinda funny that it held up better than the metal, that puts me at some ease about the JB Weld I used on my transfer case, especially since I near-surgically worked it into the crack, then coated the ENTIRE area around the drain plug quite heavily. I know it's good stuff (Seen it hold differential housings together) but didn't know it was that good. While I'll have the car in the garage, and it'll be warm-ish in there pulling my amplifier out tomorrow, I may go ahead and throw some on anyways - just to make sure I get through the cold months with no issues. I'll be sure to get pics if I do.
I've used my share of JB Weld 2-part in the tube, but i would not want to try and apply it with the housing installed. If one is inclined to try something in situ, consider products like:
That is the direction I will attack it from if we start to see more reports of failures, like we have seen in other places: HPFP, transfer cases, camshaft controller bolts, ...
02-01-2018, 04:10 PM
2011-2014 V8 - serious issue - Coolant Pipe Glue
