https://www.6speedonline.com/forums/...ml#post4074180

have a small oil leak on the rear riverside of the engine on my 997.1tt (2007)

any clue to what is leaking and if it is worth fixing (diy) or dealer it?

 

This leak could be from a few places. There is a good chance it is coming from a turbo seal.

 

Xboxfan, your leak is fairly common with the 996TT, 996GT3 and 997.1TT. Looking at your pictures, there are two possible areas to look at.


1) Each bank of your engine has a scavenge pump mounted on the exhaust cams. You will see a return line/hose that screw to a fitting. It is this fitting that has a aluminum sealing ring that is the culprit. To fix this you must loosen the return line and remove the fitting. From memory, the same aluminum sealing ring is used on your oil drain plug.


2) The other likely place is the orings that are fitted between the scavenge pump and cam housing. There are a total of 3 orings, they would be replaced when the scavenge pump is removed.


If you have a warranty in place, I would get in touch with the local Porsche Dealer.

 

Thanks, I think its option 2 that is the issue, I will talk to Porsche and see if they can take the car in its current state.

 

I agree with my learned "colleague" where the Oil is possibly coming from.

I would add, go buy some Cleaning solvent in a can and clean off the areas in question, run the engine up to operating temps and re look to see where the exact leak is coming from.

I can tell you the machined O ring grooves in the housings suggested in the other post do not allow for enough crush on the O ring to seal when all parts are heated to operating temps. We often fit a larger cross section O ring to stop this. A common fault on all of these engines.

To be sure, clean and recheck.

 

Ok but if I dealer it they will refit stock o-rings so how big of a hassle is removing the pump and replace o-rings?

Do the engine need to come out or not?

 

The Pumps can be removed in the car I'm sure, but how other stuff has to be removed, I am not sure as I never see cars. The std O ring is 21mm x 3 mm. We often fit a 3.5mm wide O ring that give another 0.020" crush. Make sure the abutment faces of the cam deck and cam covers are aligned, flta and have no scoring marks as the O rings sit and seal up against these faces. So many times the Cam covers and Decks are not cared for as they should and sealing surfaces get marked and scored. The O rings are 70 Durometer hardness I think, and it becomes difficult for the hard O Ring to seal. Check this and as the other post suggested check the sealing washers under the male fitting.

 

My fellow "colleague" has just touched of a problem that we are seeing. Oring failures on critical sealing surfaces. The heat from the turbine and exhaust system hardens these orings over time. My recommendations to those that want to research a good product is Dow Corning product called MolyKote 55 Oring lube. Here are some of the benefits:


1) Oxidation resistant


2) Heat protection to 351F 177C


3) Slightly swells rubber orings for better sealing.

 

Funny, a long time ago I worked with non-destructive testing in nuclear power plants. We used other molycote o-ring lube for our underwater equipment

 

Any clue to the part numbers for the o-rings used? Might look at doing this myself since Porsche wont do warranty work on the car since I have an aftermarket exhaust

I had a good open talk with the manager of the shop where I bought the car. He said Porsche audits their workshops to make sure they dont let any aftermarket stuff go unnoticed on cars under warranty.

He even mentioned a Swedish Porsche dealer/workshop being in trouble for allowing warranty work on cars with non N-certified winter tyres.

FYI they voided warranty on those cars due to the tires!