7391420

I 3 friends who have 997.2 cars with 40-60k miles and 2 out of 3 have had issues with carbon buildup and oil blow by-

I personally had this issue with a Mini Cooper. I'm interested I seeing how prevalent this is as the cars age?
Maybe sticky next to the IMS stickey?

Wayne Smith

I've got 42 going on 43 K on my 2010 C4S. I bought it last September with 35K. I have yet to burn a drop of oil (or blow by and humidity are working to make me believe that). I've done 2 oil changes and all looks good. I have not scoped the chambers so I can't speak to build up. The car runs great and at idle there is absolutely no waver on the tach. The exhaust tips appear to be fine. The only "smoke" is humidity on some morning start ups. I do park her on a level surface.

I've heard that the break in is critical to oil burning (or not). Carbon build up (or not) would seem to be independent of break in, but maybe not ... Extra load on the AOS would be my biggest worry in a poorly cared for car.

This topic definitely is of interest to me. I suspect to others as well. Any information is welcome.

StormRune

Also note that driving these cars mildly all of the time can result in carbon build-up problems. They are made to be driven hard, at least on occasion. I'm just under 40k and still see no decline in my oil level between changes (around 7500 mile intervals).

utkinpol

kinda interesting how come no one complained here about carbon buildup, ever, since 997.2 came to life in 2009.
not a single time.

Lvt19672

Carbon build up is the new IMS for 997.2 owners.

Wolfk

Carbon build up on the intake valves will not destroy your engine like a failed IMS bearing can. At worst, it will limit horsepower. So no, it is not the new IMS for 997.2 owners.

Tcc1999

How exactly did you arrive at this conclusion. Honestly, I am not being sarcastic. I have a basic understanding of how the DFI engine works and how it may be prone carbon build-up but I always like to learn more. Does operation at 3K RPMs or less further decrease the already less than efficient ability of these engines to "self clean" (for lack of a better descriptor).

CAVU

IMHO, a sticky for a second hand report of others' issues is not appropriate. They should join the forum and share the details (pictures, service notes, repairs, etc) behind their respective issues. Lot's of experience on the forum that might help them resolve the issues. Just MHO.

Wayne Smith

I'm not sure that there is an ultimate answer here. Carbon buildup on the back of the valves implies carbon based material in the intake. The most likely path for this is past the AOS (air oil separator). The AOS can overload and fail. That starts letting hydrocarbons into the intake.

Oops.

Running hard heats the oil, burns of humidity, and (I believe) puts less burden on the AOS.

On top of that, running hard can be a lot of fun, and I'll take any excuse I can find to make such behavior purposeful!

It may be a placebo, but I know for a fact that my car runs better after a good romp. Does this really help the AOS? Does this really burn off carbon deposits? If you ever meet my wife, the first thing you need to do say is yes, it does!

snake eyes

It seems like these threads pop up every once in awhile. Im unaware of any issues, as is my local porsche dealer.
I don't see AUDI's problems that plague the S4 as Porsches 9A1's.
BTW quality of gasoline means a lot to in engine and carbon build up more than running it hard which also has its side effects.

BrakingBad

I thought PDK failure was the new IMS for 997.2 owners. How many irrational fears should we create?

CAA

I can't tell if you're trolling or actually serious but I had a laugh nonetheless.

PM me in the morning so we can get started on our carbon build-up bearing.

$$$$$$!!!!!!!

andy92782

If I avoided driving my 997.2 on short trips because I feared excessive carbon build-up then I may as well sell the car - it would never get driven. Then I'd have to replace it with something else that, presumably, has traditional port fuel injection rather than DFI. Not as many choices these daze.

The reason we haven't heard much about this problem yet on the 9A1 is (IMHO) because P-cars simply aren't out there in the same numbers as BMWs and VWs, and the ones that are tend not to rack up the mileage at the same clip.

The 9A1 might be better at mitigating carbon build-up than some of the other engines out there but I'm pretty sure the problem can't be completely eliminated.

Bruce In Philly

2009 C2S coupe, 75k miles.... no joke, I use less oil today than ever..... always used less and less.

Carbon buildup on what? The DFI injectors shoot on to backs of the opened valves.

Peace
Bruce in Philly

hBomb

Sounds like it's time for Porsche mechanics to take a silly page out of the BMW playbook and get into walnut blasting!

http://www.e90post.com/forums/showthread.php?t=682116