I changed my oil maybe in March and put in about 6.5 qts of 20W50 into the 944 (has a turbo pan). That was enough to bring the oil level on the dipstick to the middle of the measuring area.

On Monday I checked the oil (cold engine) and the stick was dry. I had to add about a quart and a half to get it back to the middle of the stick.

All gaskets and seals and piston rings on the engine are about 3 years old (full rebuild) and it does not appear to be leaking anywhere (car sits in the same spot 5 days out of the week, sometimes longer, and there are no drips whatsoever) but I have not been able to notice any oil burning. I have no smoke in the exhaust and when I put my hand behind the tailpipe no matter how long I stay there the exhaust smells clean and perfectly burned.

How could I lose so much oil with so little driving? I have a hypothesis that since the car sits so much and then when it finally does get driven it gets driven hard (only once at operating temperature) maybe my oil is blowing by the rings on the first weekly startup.

 

Its not in the coolant tank is it?

I doubt that much oil is going by the rings when you start it up. I have an old truck that only gets started a couple times a year, and it doesn't lose any oil when I fire it up.

If its not leaking out the seals, maybe you forgot to tighten the drain plug?

 

After oil change, did you start the car and then check the oil level? On first start the oil filter sucks some of it and keeps it in there.

 

yea, i filled it to 5 qts, started it, checked it, shut it off, added a 6th, started checked and added another half qt and drove it. was fine later.

drain plug is tighter than a teenager (you can thank my dad for that adage) and like i said there is no evidence whatsoever of any oil drips on the ground or anywhere on the engine.

my coolant is clean and orange as if it just came out of the bottle. AOS had its seals replaced along with everything else.

i did have to put a new o-ring on my dipstick though, could i possibly be losing oil vapor through the dipstick hole even though its tight?

 

Is there any oily residue in the intake manifold? Do the plugs look clean? How many miles on the car since that oil last change and did it drop all at once or is this actually the first time you've checked oil level since March?

 

My mechanic always advises me to check the oil when the engine is hot to avoid false readings. However I don't see how a quart and a half can disappear because of temperature.

 

manifold is pretty clean, always has been since i hot tanked it in 06...plugs look good, less than 2000 miles since the oil change i think and no ive checked it since but between the last check (few weeks ago maybe) and monday it lost 1.5qts.

like i said i dont drive the car too much (it stays in san diego while i am in riverside for school about 80 miles away) so i dont get many chances to check the oil.

 

As much as I don't want to say it, I'm going to say "user error"....

I think maybe you had the car parked on a slope when you filled it, and saw that it was full so you thought "7 quarts went in".... or something to that effect.

A quart and a half would leave a mammoth puddle under the car. A few drips thins out on the ground to a 4" circle, so a quart and a half would leave a 4 foot circle. A quart and a half in the coolant would be instantly noticeable. A quart and a half going past the rings and out the exhaust would warm the planet by 30 degrees.... you get the idea.

Thats a lot of oil to just "lose". I think you would have noticed it somewhere at some time.


Sorry......

 

I had a similar thing happen to my S2. The oil seemed to disappear shortly after refilling with new oil. It was especially bad when the car was started on steep slope - it was like having it on a slope released an air lock in the oil system somewhere and all of a sudden the low oil warning light comes on. It also didn't necessary happen immediately after filling. It would be OK after a drive, but then park it on a steep slope (1 in 6) and it would disappear (yes it was checked on a level surface). Top it up and never disappeared again.

Oh, and another thing, dont use an xW40 or thinner oil - my experience with these is high oil consumption if the car is driven hard. Use a W50.

 

my driveway (where all work whatsoever is done) is almost perfectly level. in addition i buy oil by the case so i know that when a 12 bottle case has 5 bottles left that i have enough oil in mr porsche

also, i checked the oil the other day in almost the same spot that i changed the oil last.

maybe ill just change it again and see what happens

 

I could see if it was veggy oil and the local strip club was low, they might steal some...

Perhaps you hit your head whilst changing the oil.

 

I don't know what to tell you Spencer. Thats a lot of oil to have gone missing.... and then to add again.

If you do find it, let us know.

 

You should keep oil level near maximum mark. Add oil and check how fast the oil dissapears.
Max allowed oil consumption is 1,5 liters per 1000 km.

 

ill start over with 7 new qts asap and track it then. guess ill do a going-over of seals...

what to check that would lead to excessive oil burning?

 

Time for an LSx swap.