Excessive oil consumption

I have a 2003 996 C2 that I bought new in November '03. The car now has 9300 miles on it. The oil consumption appears to be way out of whack and I can't figure out why. Between 0 and 7900 miles I must have added 6 quarts since the bars on the dashboard "check engine oil" indicator were at the lowest level and I could barely get any oil registering on the dipstick. I would add a quart periodically and after 800-1000 miles it would be back at 1 bar. I am now driving the car throught the winter and I took the liberty of having a very reputable Porsche mechanic change the oil in anticipation of winter. That was at 7900 miles and after the oil change the bars and the dipstick were all full. As I said, the car is now at 9300 miles and we're back at 2 bars and trending to one! The dipstick also shows that the oil is at the first marker. By the way, there is no oil on the garage floor at all and the mechanic said the car showed no leakage at all from underneath. Any idea what the heck is going on here?

I too have an '03 996 C2. I purchased mine in August of '03. She burned a quart in the first 2,000 miles and hasn't burned a drop since. I did make a point of doing alot of up and down rev cycles with the car in gear in an attempt to make sure that the rings seated properly. Maybe that helped. Six quarts sounds like too much to me though I guess a quart every thousand miles is considered "normal." I'm sorry I can't be more helpful.

lots of opinions on this topic if you do a search but there is no way 6 quarts can be right ....

Mine also uses a qt every 1500mi, broke it in by the book, no oil on the floor, no smoke..... diagnosed with an RMS yesterday. Still I don't think that accounts for all of my oil use, I think the rings seat poorly in these engines. Have your mechanic take a good look underneath the car, as I found out you don't have to see oil spots to have an RMS. Chris

Can someone tell me what RMS stands for and what it means. Way too many threads that mention it without any answering those 2 questions. Thanks.

RMS=rear main seal....althought it is technically called the crankshaft main bearing seal.

Funny thing about those main seals, of all the small block chevrolet racing engines that I either built or had built in my previous life, I never once saw one leak a drop. Those engine ran as high as 8-12000 rpm's made 600+ HP and used a crappy c-shaped rubber seal. Maybe the RMS thing is just a fundamental problem with the design of the m96, who knows? I don't.

Mark: Sounds like the rings haven't seated. Did you change your oil early? Drive the motor near redline more often and vary rpms in big swings. Everthing elase is broken in by now. my .02

I suspect that if I ever blow the seal that I would install the new one with a SEALANT, regardless of what Porsche recommends. It appears that there install procedure doesn't work anyway.

If the shocks Porsche installs are good for the "life of the car"(per you)....why would you have to replace a seal? or anything else for that matter?

A man was walking down the street and saw an Eskimo looking at his car tire. So the man said, �You blow a seal?� And the Eskimo responded �No. That''s just frost on my mustache.�

" though I guess a quart every thousand miles is considered "normal."" I think that's BS sponsered by Porche. With todays metalurgy, tolerances are closer (less bypass on warm up). To paraphrase, It's not unusual - but it ain't normal.

Mark, get Porsche to record your complaint of the amount of oil you are burning and have them respond on the repair order that it is normal. I doubt they will do so, but worth a try.

Iron to iron motors. To be fair, Pcars have to deal with aluminum & steel, with different rates of expansion/contraction and different strengths (Can't have alum bore, too weak).

I agree with you. I'd be pissed if any car I owned burned that much oil. And I feel very fortunate that my '03 doesn't burn a drop of oil between oil changes. But I did make a concerted effort to seat the rings during break in through repeated reving under load cycles. Perhaps the rings are so hard as to require serious seating through hard accelerations and decelerations through the RPM range. This may be a situation where babying your P-car during break-in may in fact be detrimental. But who knows? I'm no engineer.