Disclaimer: This isn't a full step-by-step DIY with pictures of each step because I was pressed for time during this installation. However, I don't think there is a better DIY out there yet, so go ahead and give this a read if you're going to attempt to do this job. I will be happy to answer any questions you have about it to make up for the lack of pictures here.


957 V8 Thermostat and Water Pump Replacement


This weekend I performed the thermostat and water pump replacement on my 957 Turbo S. The procedure should be almost identical on all 957 4.8l V8 Cayennes aside from the extra air piping involved with the turbo cars.

I was getting a code, P2181, which was telling me that the cooling system was not getting up to temperature in time. Also, the coolant temp and then the oil temp would drop at highway speeds in temperatures below about 60 F. I figured the thermostat was at fault. I also decided to replace the water pump and serpentine belt while I was in there for preventative maintenance. For reference, this pig has about 84k miles on it. Symptoms started occurring at around 79k, but it was warm enough that the slightly stuck open thermostat didn't matter.

There are a few "special" tools needed for this job. This picture shows all of the tools i used to do the job. Notable tools needed are:

-30 mm wrench
-Torx - T40 for water pump pulley removal
-Torx - T30 security (only needed if replacing serpentine belt)
-ETorx (inverted Torx) T?? for water pump removal NOT PICTURED
-Torx - T25 screwdriver for throttle body removal

The other tools needed are a flathead for removing hose clamps, and some pliers for removing those danged spring clamps. A spring clamp tool would be very nice to have for this job, but is not required.

*note* VIM tools makes a very nice and comprehensive set of Torx bits which you may be interested in when working on just about anything German. It is available on Amazon and I would highly recommend it. They also make a great triple square set. The bits are made in China, but the quality is on-par with the best out there based on the products I've bought from them.




Here are the parts I ordered for this job. Not all of them are essential, but I did't want to have to do the job twice and only had a limited amount of time to do it, so I went a little above and beyond. All parts were ordered from ECStuning.com. They have the best prices and were able to get everything for me promptly.

- Water pump - 94810603301
- Water pump pulley - 94810609100 (not required, but I replaced mine just because it's plastic and after another 80k miles of heat cycling, you never know what might happen to it!)
- Serpentine belt - 94810653300 (not required and not pictured, but not a bad idea to do while you're in there)
- Thermostat - 94810612501
- Coolant - 00004330149 (I only needed about half a gallon, but had extra on hand just in case)
- Special lube - 00004320593 (not really required, but again, I didn't want to have to do the job again)
- Intake socket - 94810610103 (This is the stock part number. The stock part is plastic, but an aluminum version can be found at ECSTuning.com by searching for that same part number)





The intake socket is an interesting part. I chose to order one which is made from aluminum rather than plastic like the stock part. I figured this would be good from a longevity standpoint. The aluminum version is based on the latest revision of the part from Porsche and includes the "upgraded" round o-rings. The other o-rings and lube used by Porsche in the previous design led to leak problems. The only problem with the aluminum intake socket is that you may have trouble getting it out the next time the thermostat needs to be replaced. I will go into a bit more detail on this later.


Unfortunately I don't have too many pictures of the disassembly process required to get to the water pump. It is fairly simple however once you realize that how the Y-pipe comes off. Just loosen the hose clamps on the accordion flex pipes and twist the whole y-pipe assembly clockwise.

Removal of the TB is best done with a T25 torx screwdriver. I also moved various hoses aside. I only really had to remove the upper coolant hose on the driver's side of the water pump. This can be done with minimal coolant loss if you're careful. A few small misc. hoses and b**** clips later, and you'll have a clear view of the water pump area.

Break the water pump pulley bolts (T40 torx) loose with the serpentine belt still on. Then use your 30 mm wrench with the closed end on the tensioner bolt to put slack in the belt and remove it from the water pump pulley. Now you can remove the pulley and water pump (requires inverted Torx).

At this point, you should have a clear view of the intake socket.





Removing this part is probably the most difficult aspect of this job. Unless you have or can make a special tool, you will need to use the brute force method to remove it. I found it easiest to use a flat head screwdriver with a hammer to split the socket on it's bottom half. It should break apart fairly easily with minimal fear of marring the aluminum housing. Eventually, you should be able to pull it right out.

This is what mine looked like once removed.




At this point, I realized that the aluminum intake socket might not be the best idea to install in the event that I need to replace the thermostat again, however, I didn't have a different one. I'll just have to try to acquire the special tool when that happens. Here's a picture of the aluminum intake socket.





The thermostat is right behind the intake socket and can be pulled out by hand.

**As a side note, I didn't really think the thermostat seemed so bad when I took it out, but I did notice that the temperature sensitive part of it was a bit loose inside compared to the new one. Also, the water pump I pulled seemed to be in OK shape, but it did have some play in it compared to the new one. I feel much more comfortable having a new one in there. **

When installing the new intake socket, Porsche recommends using a special lube and diluting that 50:50 with water. I found this also useful for installing the thermostat. Both the intake socket and thermostat are able to be pushed in by hand.


The rest of the installation of new parts is the reverse of the removal.

However, if you're replacing the serpentine belt (which is a good idea to do if you're around 80k miles like I was) I have a few tips. The belt routing is fairly complicated and requires disconnecting two hoses and one bracket. The hoses have those stupid quick connects on them which are extremely difficult to disconnect by hand, and the small bracket requires the removal of a T30 security torx bit.


I will post a few more pictures detailing locations of certain parts at some point... feel free to add your input here!

 

Porsche is really replacing all that plastic composite in the Cayenne coolant system. When I replaced my intake socket about 2 years ago, the new part was still plastic composite

EDIT: Wait a minute, I thought this was a stock part. Looks like this is aftermarket. Who makes an aluminum socket replacement?

 

Since the original post is well done and it is a major maintenance item that everyone will need, I think it justifies a "sticky". Done.

 

You are correct, that is not a stock part. When I was searching for information and pictures on parts I'd need to do the thermostat via google, I kept finding pictures of this intake socket in aluminum. I couldn't really find anywhere which specifically listed an aluminum version though. I searched and searched, even on ECS tuning, but I didn't order the parts until a few weeks ago. When I finally went to put the parts in my cart on that same website, I discovered that they now list an aluminum version and even have new pictures of it.

Here's a link:

http://www.ecstuning.com/Search/Site...103/ES2771205/

The part is well made by a German company called Hamburg-Technic, but beware of the issues that may arise when it comes time to remove it! Hopefully that won't have to happen for another 80k miles.


Thank you for making this a sticky. I wish I had more pictures, but as I said I will be happy to answer any questions related to this and hope to edit a few pictures to try and illustrate a few points.

 

Believe it or not, Hamburg-Technic is actually the OEM manufacturer for many parts on our Cayenne. Not any different from Bosch, Denso, Mahle, Brembo, etc.

To corroborate, here the 955 aluminum coolant pipe and 957 aluminum coolant pipe from the same company:

http://www.ecstuning.com/Porsche-200...ipe/ES2771199/

http://www.ecstuning.com/Porsche-200...ipe/ES2771201/

So since this part exists at Hamburg-Technic, it must have been made specifically for the Cayenne 4.8 DFI engine. Which also implies there has to be an official Porsche part number for it.

Just wish there was a good way to do a part number cross-reference between the two companies

 

Great timing & great write-up Thanks! I got the damn thermostat code & will be doing this on my 09 CTTS @ 39k miles.
Was planning on taking it to the dealer & having it done with Ext. Warranty, but I think I can handle this myself (I trust me more). Only part that makes me a bit nervous is whacking/breaking the intake socket to get it out. Was wondering how tight it is in there & if a (makeshift) puller on the thermostat might be able to pull them both out? Not sure I want to risk damaging the housing by the brute force method.

 

Sorry for not responding to this sooner. I thought I had already.

You can definitely make some sort of puller to get it out. I just didn't have the resources at hand to do so. If you get a thermostat in-hand, you can easily determine the dimensions for the puller you've have to make.

Honestly though, if you take your time the "brute force" method isn't very dangerous. I was concerned with nicking the housing too, but it came out unscathed. The plastic is really thick and it will crack nicely before you ever get the chance to chip into the aluminum housing. You can also pretty easily avoid the area where the o-ring seals by comparing the new part you will have in-hand.

 

Thanks again Lox
Going to tackle this in the next week or two, if I create a puller I will document & share with the group.

 

the shop manual recommends wrapping wire around the thermostat spring and pulling it out using a screw driver.
I ended up fishing a handful of zip ties through the spring and using a long wrench to pry against the housing.
the thermostat and water intake socket popped out without too much force.

on the inner o-ring of the intake socket you can see the cream colored crud build up.
I think this is the 'too much' lubricant during assembly causing leakage indicated by the tsb.
mine wasn't leaking but a new intake socket including o-rings 948-106-101-03 was only 24 bucks, the new special lubricant 000-043-205-93 was 19 bucks.
I diluted it with water 50/50 according to the tsb and used a small amount on both o-rings. the intake socket slid in easily.

 

is there a substitute for the grease or do we need to buy the $20 special one from Porsche?

 

you could probably use a different product designed for o-rings and cooling systems.
maybe even dow 111 or similar, but what would you save? 10 bucks, or even 20 if you have something on hand.
if the o-rings and water intake socket leak you are out hours of your time to take it apart and reuse the fancy porsche lubricant.

 

I am tackling this job today. I talked to a Porsche parts guy and he said no need for the special lube. He said his techs put a little coolant on the socket and pop it in.

 

Did the same, no leaks

 

I finished the job, replaced the thermostat, and put everything back together no leaks. The problem still continued, same engine code after I reset it. Engine doesn't reach 185F until 15 minutes or never.

Did I get a defective thermostat or is there some kind of seal I'm missing? Cold water is still getting around the thermostat somewhere. The thermostat isn't stuck open so I'm not sure how its having a hard time heating up.

Is there some other cause that I might have missed? Auxiliary heater pump? Seal?

I'm going to pull it back apart and going to test the thermostat in a boiling pot of water. If the thermostat test okay I will be lost. Its obviously not stuck open.

I attached some photos

 

For those looking for a manual to make this task easier this might help
http://workshop-manuals.com/porsche/...ce_and_repair/