russo

Greetings everyone. I have been an avid reader of Rennlist for a couple of years. This is my first post in this forum.
My 2002 996 C4 conv. had it's rear main seal replaced 2x, the first I paid and the second the dealer covered the cost, mileage is 41,000. Prior to the main seal replacement the 996 required 1 qt of oil every 600 miles. Post rear main seal, it consumes 1.25 qts every 300 miles, no smoke or oil drops noted. To say the least, this has me very concerned. The dealer has always maintained that the 600 mile consumption is within spec. I have not spoken to the dealer regarding this concern and I am hoping to get some feedback before I approach this subject. Originally I had purchased this car with 24k miles. My 2007 997S with 4K miles has not consumed a single drop, even though I track it on a monthly basis. What's up with this? I really love the 996 and won't even consider selling it.

Current Vehicles:
2002 C4 Conv
2007S Conv
2006 Cayenne Turbo
2001 Honda Accord, my daily driver/bread winner
2004 Cayenne S sold and forgotten

cdodkin

Doesn't sound right

You sure your bell housing isn't filling up with oil?

1999Porsche911

Have you tried a better oil?

Jon996

Greetings! I just wanted you to know that you are not alone . . . While I have not had a RMS problem, my oil consumption has "went south." I am really surprised they will not take action as you are well below the magic number of 1 qt per 600 miles.

Funny, also like you I really like my 996, and will do about anything to keep it going. [OT: Why do Porsches do this to us? My Toyota has never been in the shop, burns no oil, has no creaks anywhere, but also has no emotional attachment . . .]

FYI, here is my story on this:

Situation: Oil consumption on used 2003 996 C4S was running about 1 qt per 1500 miles. Not great, but not bad (no need to chime in if you have zero consumption just to make me feel bad ) Then over the winter, as I drove the car, it went down to 1 qt per 600. So I figure I will head into the shop for a check. They do a formal oil consumption check, which, by the book, involves topping off the oil cold, driving 600 miles, then reading it cold. Now the annoying part (minor rant). They confirmed 1 qt per 600 miles, but then produced a TSB that stated 1.1 qt per 622 miles was the actual standard, thus they could not look into it. Since I am an engineer by trade, I pointed out that a dipstick is hardly a precision instrument. However, they sent the query on to the regional technical manager (probably an accountant) who denied action.

FYI: Never any smoke. Might be excessive soot from right exhaust, but some from left too. The car runs really quiet, no obvious power loss that I can tell, no weird sounds, no drips anywhere.

OK, I have a year left on my CPO, so I can wait a few months then go back in for a precision dipstick measurement, but I was also thinking of taking some action (at my expense) now. One item that comes to mind from other threads on this is to try the 2 chamber Porsche Motor Sport oil separator. Porsche OEM-996 107 926 00. At least even if this did not help it would be considered an upgrade from the stock unit.

Ray S

Welcome

Your oil consumption sounds a little high in my opinion. How often do you drive it (daily driver or once a week)? Mostly long trips, short trips or both? Has this consumption rate been consistent or does it fluctuate quite a bit?

nycebo

Guys, this sounds absolutely abnormal. I drive a 2000 C2, have the same engine, and can't even remember the last time that I had to add oil to the car. I might guess it's every 5000 miles. Maybe it's because of my routine annual oil change? Anyway, I would definitely get myself into a different service tech and have the car looked over.

Jon996

Hi! I am not sure if the OP still has warranty via CPO, but a dealer will not look at anything (at least my dealer--limited choices here) unless your consumption hits a certain level.

redridge

it may not appear its burning oil... but it has to be going somewhere. Do you have a sweaty oil bellows (bellow the air oil seperator) it is located under the driver rear axel area?

perryinva

True, you may only have a leak under high oil pressure, so you would never see any onthe garage floor. No dealer in their right mind would say a qt of oil per tank of gas is normal...& I still think a qt every 2 tanks is still very high.

gregorycarl

I never need to add oil to my 2000 C4 between changes. Boxster was another story which required half a quart every 1,000 miles or so.

nycebo

Gregory, I never had it with my Boxster S either. A friend of mine has been commenting about using a lot of oil in his 997S. He tells me that it's about 1 quarter every 1000-1500 miles. The service tech says that acceptably, but I am stunned that I never really seem to be adding oil between changes. Odd.

Have you checked on RennTech also? They may have some experience with this also.

UPDATE: This post had some pretty good insights that may pertain to you.

cdodkin

Porsche dealers seem to quote the 1qt every 600 mile cut-off as there threshold for reviewing if there is an issue.

Clearly that has been passed in this case.

1.25 qts every 300 miles is like running a 2 stroke engine!

As other have pointed out, it's either going somewhere or being burned during driving.

Note - the 996 can exhibit a high moisture content in engine oil when used for repeated short trips.

This moisture can then 'burn off' on longer trips, giving a visual impression that the oil level has decreased - worth bearing in mind, depending on vehicle use patterns.

Are you noting that the oil consumption was a step change when the RMS was done - or are you just using that event as a time marker?

ElTorrente

I have over 115k miles on mine, and it burns ZERO oil between changes (around 7.5k). The electronic gauge doesn't move, and the level on the dipstick confirms.

1999Porsche911

You better bring it back to the dealer so they can correct your obviously, faulty engine.

ElTorrente

Yeah - I think it's gonna blow-up anyday now.