dgjks6

2009 carrera 4 cab, just passed 11k miles. First 5k miles I put on it used 1 quart of oil. Last 700 miles used 1 quart. Tail pipes are black. I mean black.

Car is CPO so let the fun begin.

mreloc

Hopefully it's just the AOS! Good luck.

dgjks6

Thanks

Best part about CPO is I don't care. The have 20 months to figure it out. Hope I get something cool for a loaner.

mreloc

I see your point, but still it would be nice if it was a simple solution vs. a catastrophic engine issue that would keep everyone looking over their shoulders waiting for it to happen to them

ADias

Deleted

gopirates

See my thread, I had my AOS replaced under CPO at the beginning of the month due to high oil consumption and the dealership checking the oil pressure using a vacuum test.

I'm still monitoring the oil consumption and we will see if my problem has been resolved. Good luck.

Philster

dgjk, where do you live?

Daily driver or weekend toy?

Good luck.

Macster

Tail pipes being black is normal. For every gallon of (ethanol free) gasoline burned the engine produces about 19lbs of carbon most of it in the form of CO2 but some in the form of soot.

Besides the exhaust passes through 1 make that 2 converters on the way from the combustion chamber to the exhaust outlet so any excess soot at the tail pipe is probably more an indication of how the converters are working and not the engine.

Like I like to say: Soot happens.

Absent any CEL, or engine symptoms or smoking except very very occasionally at cold engine start the oil usage is nothing to worry about.

How you drive can affect oil consumption. Lots of idling or high speed/RPM running can up oil consumption. My Boxster is not too bad in this regard but if I push my 996 Turbo engine hard for very long the oil level can drop some. I suspect the AOS to some extent with the turbo seals accounting for the rest. By way of comparison, I can drive the car 4K miles at highway speeds in just a week's time and the engine doesn't use any oil over this time.

Of course you are free to keep a close eye on the oil level and oil consumptoin and document this in a diary. If the consumption gets to the point it gets too bad -- IIRC -- more than 1 quart per 600 miles then that falls into the excessive oil consumption range defined by Porsche.

If the oil consumption is high even with engine usage that is not conducive to high oil consumption the culprit could very well be a sub-par AOS. These things suck.

That oil smoke on cold start is due to the AOS allowing excessive amount of oil vapor through where it impacts the intake walls and collects as a liquid and when the engine is shut off drains down onto closed intake valves or into a cylinder if the valves are open. This is where the smoke comes from upon a cold engine start.

The AOS allowing excessive amount of oil vapor through doesn't just happen a moment or two before you shut off the engine, it happens all the time the engine is running.

That you don't see any smoking it is because the engine is warm as are the converters and these being up to temp works to burn the oil well enough there is no smoke.

But the result is oil is being consumed. I would not change out the AOS unless a test of it found excessive/out of range low pressure. Just replacing the AOS with another one might not help the oil consumption -- provided I'm right about it of course (I think I am but I have no scientific proof, no lab/field test data to offer) -- as I said about these AOS's just suck in that they are not very efficient/effective at removing the oil vapor from the crankcase fumes as these fumes are routed to the intake and engine to be burned.

(I have no recommendation for a specific product and I'm not a fan of making modifications to the these cars/engines but a "catch can" installed in the line from the AOS to the intake manifold might be a way to at least see how much (or how little) oil is being passed through the AOS.)

So I really don't think the engine is using any oil in the way a worn/defective engine, say pistons/rings/cylinders or valve guides/stems/seals would use oil.

dgjks6

Akron Ohio

Daily driver. Almost 1000 miles this last week between volleyball, track, and dance. Car had 5200 miles in Feb when I bought it. Didn't drive much in February and march because wrong tires. Since end of March put on the entire 6000 miles

dgjks6

Read that. That's what I was thinking when I first saw the oil was low at 10000 miles. Now I am really thinking that with another quart gone in the last 1000

dgjks6

Did not want to quote the entire post, but as a regular tail pipe cleaner on both my old 996 and this one, it's more soot than I have ever seen.

cool flash

Early 2009 models (produced in mid/late 2008) had a tendency to burn more oil due to piston ring tolerances being too high. Porsche replaced the rings on those under warranty (at least here in Germany).

Check the production date of your car and inquire with your dealer.

Regards,

CF

user 72902

19lbs per gallon?

Fahrer

It is a 2009 with DI. DI engines produce more soot due to fuel droplets hitting the pistons. This is why some engines are using both DI and port injection. DI gives better cooling but port injection gives better fuel air mixing.

Carrera Mike

Dgjks,

While engine is cold, check your coolant tank for oil water intermix(I highly doubt this is the case). If no trace of oil, my suspect is the AOS. I myself replace the center and aft AOS. The front right, I can not reach/access. Then I made this oil catch can... https://rennlist.com/forums/997-foru...catch-can.html