Oil consumption
06-03-2008, 02:28 PM
#17
Nordschleife Master
My C4S with oil changed in April, this weekend burnt through 1 litre of oil/per day, driving conditions for each day: 80 min aprox 140 km at 5000 to 7000 rpm. 80 min aprox 80 km driving 2000-5000 rpm and 150 min 300 km driving at 2000-3000 rpm.
In total for the day 5 hours of driving a distance of aprox 520 km 1 litre of oil and 2 tanks of gas.
In total for the day 5 hours of driving a distance of aprox 520 km 1 litre of oil and 2 tanks of gas.
Last edited by jumper5836; 06-03-2008 at 02:45 PM.
06-03-2008, 02:34 PM
#18
Drifting
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My C4S with oil changed in April, this weekend burnt through 1 litre of oil/per day, driving conditions for each day: 120 min aprox 140 km at 5000 to 7000 rpm. 120 min aprox 80 km driving 2000-5000 rpm and 150 min 300 km driving at 2000-3000 rpm.
In total for the day 6.5 hours of driving a distance of aprox 520 km 1 litre of oil and 2 tanks of gas.
In total for the day 6.5 hours of driving a distance of aprox 520 km 1 litre of oil and 2 tanks of gas.
06-03-2008, 03:14 PM
#19
Nordschleife Master
modified my original post a bit, but yes the consumption is very high when under heavy load. This is me at the track driving the car full out and always at peak hp. Then my wife at the track taking it easy and then the drive to and from the track and a trip to the gas station under very little load.
I just checked my oil level this morning after 2 days of this and it is now at the last bar before it reaches min.
So that is 3 liters it's gone through. Anybody else burn this much oil tracking your car?
My RMS is sweating but there hasn't been a drop of oil on the garage floor. I did have slight smoke up at startup once this weekend and no one behind me at the track noticed any smoke from my car while on the track.
I just checked my oil level this morning after 2 days of this and it is now at the last bar before it reaches min.
So that is 3 liters it's gone through. Anybody else burn this much oil tracking your car?
My RMS is sweating but there hasn't been a drop of oil on the garage floor. I did have slight smoke up at startup once this weekend and no one behind me at the track noticed any smoke from my car while on the track.
06-03-2008, 03:20 PM
#20
Drifting
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modified my original post a bit, but yes the consumption is very high when under heavy load. This is me at the track driving the car full out and always at peak hp. Then my wife at the track taking it easy and then the drive to and from the track and a trip to the gas station under very little load.
I just checked my oil level this morning after 2 days of this and it is now at the last bar before it reaches min.
So that is 3 liters it's gone through. Anybody else burn this much oil tracking your car?
My RMS is sweating but there hasn't been a drop of oil on the garage floor. I did have slight smoke up at startup once this weekend and no one behind me at the track noticed any smoke from my car while on the track.
I just checked my oil level this morning after 2 days of this and it is now at the last bar before it reaches min.
So that is 3 liters it's gone through. Anybody else burn this much oil tracking your car?
My RMS is sweating but there hasn't been a drop of oil on the garage floor. I did have slight smoke up at startup once this weekend and no one behind me at the track noticed any smoke from my car while on the track.
Suspect that it's all burning-off in use - but it's still quite a throughput.
You getting a lot of soot in your exhaust pipes?
Only other point of inspection I'd suggest could be the air/oil separator bellows, they can puncture and leak (not good).
06-03-2008, 03:29 PM
#21
Nordschleife Master
I am not getting abnormal sot on the exhaust pipes. This winter a did 4000 km and put maybe 2 liters of oil in the whole time. I drive it short distance daily and fill up the gas tank once a week. Maybe once a month I need to put in 1/2 liter of oil.
06-03-2008, 04:42 PM
#22
Three Wheelin'
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pull the oil separator tube off your throttle body and see if there's oil in it. if there is, the membrane in the oil separator has gone bad and you're sucking oil in through the throttle. this is probably the most common cause of your problem on the M96 motor variants.
06-03-2008, 06:13 PM
#23
Rennlist Member
Thanks for the very useful suggestion. Just so I do not do something stupid, do you (or anyone else) have a photo or schematic? Thanks again!
06-03-2008, 07:30 PM
#24
Three Wheelin'
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the tube is on the side of the throttle and is about 3/4" in diameter. to undo the tube, pinch the plastic collar and pull it off the throttle. dip your finger in it. if there's oil in it, you have found your problem. FYI, a new oil separator is about $100 from sunset imports. it's a pain in the butt to install. unless you're patient & wrench savvy, pay the guy.
06-03-2008, 07:52 PM
#26
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Here's a photo of the actual separator - outlined in red (again 986 Engine)
When mine died (986) It made a noise like a blue whale falling from 30,000 feet - so I was lucky to get an audible clue as to the issue and it's location!
When mine died (986) It made a noise like a blue whale falling from 30,000 feet - so I was lucky to get an audible clue as to the issue and it's location!
06-03-2008, 08:02 PM
#27
Race Director
Second that suggestion to check for a failing AOS that can suck oil...
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
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
right out of engine. Even if engine subjected to a bit more vacuum at the inappropriate times, vapor more heavily loaded with oil droplets will be pulled out of engine before the separator has time to remove these and this oil will be burned.
'course, you have to have engine checked over very thoroughly for any oil leaks.
(I had another car that leaked oil, but nothing showed up under car, or anywhere on any other car parts. The oil was dripping out a valve cover gasket down on to a hot exhaust manifold and the oil was being vaporized from the high heat of the manifold. The leak would subside before exhaust cooled enough. The only way I knew oil was leaking was I smelled it when I shut engine off and sometimes when I started hot engine I'd see a puff of what was oil vapor coming out around hood gaps. Service manager looked engine over and to his credit spotted stained area on exhaust manifold that was from the oil dripping down on it when hot.)
An engine has to really use a lot of oil for it to show up as smoke in the exhaust. When it does, usually it comes during a time when the engine is not actually burning any gas -- like on closed throttle coast down -- so the oil goes through the engine unburned and what you see is oil vapor.
One 'trick' is to with sun low behind you drive car and watch for a haze/light light smoke. With sun high overhead or facing you as you drive car...
Be very sure you accurately document oil consumption before you go to dealer. Do not rely upon memory, but sketch the oil level on dipstick and check oil after car has sat unused for some length of time. Or take pictures to show the oil level and mileage and how the car has been parked.
You want to be very scientific and thorough about this, not haphazard at all. I'd start with fresh oil/filter with oil of proper brand, grade, etc. Add an exact amount, say 9 quarts (just a number, use the right amount so oil level not too low or too high) and after letting engine sit idle as long as you can -- overnight -- check oil level. Note very accurately its position. Do not rely upon your memory. Note odometer reading.
Then every fill up, or every day even, at some parking space, check oil level and note its new level and odometer reading.
You want enough readings that show oil consumption excessive and clearly so.
If you don't do this now, dealer will likely require you to do it before it does anything at all.
Also, mention that with this high oil consumption you have lost all enjoyment from use of car, are concerned the high oil consumption is precursor to serious engine trouble, possibly subjecting you to safety risk if engine fails on busy highway in rush hour or leaves you stranded late at night. And so on.
If it applies in your area, you can have car checked to see if it still passes smog and if not, then use this a some leverage to have engine fixed.
Sincerely,
Macster.
06-03-2008, 09:17 PM
#28
Excellent post! agreed with everything stated here! Especially with the documentation part.
right out of engine. Even if engine subjected to a bit more vacuum at the inappropriate times, vapor more heavily loaded with oil droplets will be pulled out of engine before the separator has time to remove these and this oil will be burned.
'course, you have to have engine checked over very thoroughly for any oil leaks.
(I had another car that leaked oil, but nothing showed up under car, or anywhere on any other car parts. The oil was dripping out a valve cover gasket down on to a hot exhaust manifold and the oil was being vaporized from the high heat of the manifold. The leak would subside before exhaust cooled enough. The only way I knew oil was leaking was I smelled it when I shut engine off and sometimes when I started hot engine I'd see a puff of what was oil vapor coming out around hood gaps. Service manager looked engine over and to his credit spotted stained area on exhaust manifold that was from the oil dripping down on it when hot.)
An engine has to really use a lot of oil for it to show up as smoke in the exhaust. When it does, usually it comes during a time when the engine is not actually burning any gas -- like on closed throttle coast down -- so the oil goes through the engine unburned and what you see is oil vapor.
One 'trick' is to with sun low behind you drive car and watch for a haze/light light smoke. With sun high overhead or facing you as you drive car...
Be very sure you accurately document oil consumption before you go to dealer. Do not rely upon memory, but sketch the oil level on dipstick and check oil after car has sat unused for some length of time. Or take pictures to show the oil level and mileage and how the car has been parked.
You want to be very scientific and thorough about this, not haphazard at all. I'd start with fresh oil/filter with oil of proper brand, grade, etc. Add an exact amount, say 9 quarts (just a number, use the right amount so oil level not too low or too high) and after letting engine sit idle as long as you can -- overnight -- check oil level. Note very accurately its position. Do not rely upon your memory. Note odometer reading.
Then every fill up, or every day even, at some parking space, check oil level and note its new level and odometer reading.
You want enough readings that show oil consumption excessive and clearly so.
If you don't do this now, dealer will likely require you to do it before it does anything at all.
Also, mention that with this high oil consumption you have lost all enjoyment from use of car, are concerned the high oil consumption is precursor to serious engine trouble, possibly subjecting you to safety risk if engine fails on busy highway in rush hour or leaves you stranded late at night. And so on.
If it applies in your area, you can have car checked to see if it still passes smog and if not, then use this a some leverage to have engine fixed.
Sincerely,
Macster.
'course, you have to have engine checked over very thoroughly for any oil leaks.
(I had another car that leaked oil, but nothing showed up under car, or anywhere on any other car parts. The oil was dripping out a valve cover gasket down on to a hot exhaust manifold and the oil was being vaporized from the high heat of the manifold. The leak would subside before exhaust cooled enough. The only way I knew oil was leaking was I smelled it when I shut engine off and sometimes when I started hot engine I'd see a puff of what was oil vapor coming out around hood gaps. Service manager looked engine over and to his credit spotted stained area on exhaust manifold that was from the oil dripping down on it when hot.)
An engine has to really use a lot of oil for it to show up as smoke in the exhaust. When it does, usually it comes during a time when the engine is not actually burning any gas -- like on closed throttle coast down -- so the oil goes through the engine unburned and what you see is oil vapor.
One 'trick' is to with sun low behind you drive car and watch for a haze/light light smoke. With sun high overhead or facing you as you drive car...
Be very sure you accurately document oil consumption before you go to dealer. Do not rely upon memory, but sketch the oil level on dipstick and check oil after car has sat unused for some length of time. Or take pictures to show the oil level and mileage and how the car has been parked.
You want to be very scientific and thorough about this, not haphazard at all. I'd start with fresh oil/filter with oil of proper brand, grade, etc. Add an exact amount, say 9 quarts (just a number, use the right amount so oil level not too low or too high) and after letting engine sit idle as long as you can -- overnight -- check oil level. Note very accurately its position. Do not rely upon your memory. Note odometer reading.
Then every fill up, or every day even, at some parking space, check oil level and note its new level and odometer reading.
You want enough readings that show oil consumption excessive and clearly so.
If you don't do this now, dealer will likely require you to do it before it does anything at all.
Also, mention that with this high oil consumption you have lost all enjoyment from use of car, are concerned the high oil consumption is precursor to serious engine trouble, possibly subjecting you to safety risk if engine fails on busy highway in rush hour or leaves you stranded late at night. And so on.
If it applies in your area, you can have car checked to see if it still passes smog and if not, then use this a some leverage to have engine fixed.
Sincerely,
Macster.
06-03-2008, 09:21 PM
#29
Rennlist Member
This has been really helpful. I removed the tube and there was an oil film inside. Given how the separator works, I am not sure if this is more than average--is it ever completely dry in this tube? Still worth looking into. Thanks much.
I would just add a note to Macster based on my experience of a couple of months ago. Even though I had completely documented a change in consumption over the winter (a COLD winter, FYI) my dealer would do nothing without their own oil check. It came back just short (actually 0.1 qt short) of where they would take action. As an engineer, relying on a dipstick for 0.1 qt accuracy is pretty silly. Will just redo the test later this summer.
I would just add a note to Macster based on my experience of a couple of months ago. Even though I had completely documented a change in consumption over the winter (a COLD winter, FYI) my dealer would do nothing without their own oil check. It came back just short (actually 0.1 qt short) of where they would take action. As an engineer, relying on a dipstick for 0.1 qt accuracy is pretty silly. Will just redo the test later this summer.
