Oil Separator vs. Oil Consumption

The Porsche dealer replaced my oil separator on my 2002 C2, claiming that PNA says that is why I am burning a quart of oil every 600 miles. No smoke while driving, and no smoke on start-up, although the dealer claims he saw smoke on start-up. I have driven the car about 800 miles since replacement of the oil separator, and it looks like I have the same oil consumption as before, with the exception of the electronic oil gauge being more unpredictable then ever. Not really knowing what the oil separator really does, can anyone tell me exactly what this items function is, and if it would have anything to do with oil consumption? Better yet, has anyone cured their oil consumption by the replacement of the separator??? Thanks in advance, Tom L 2002 C2

The oil seperator does pretty much what its name implies. The oil seperator draws in oil vapor from the heads and removes the oil from the air and returns the oil to the case. A failed diaphragm in the oil seperator can cause high oil consumption but it will be accompanied with A LOT of smoke from the tail pipes on start up and usually a check engine light.

PTEC, Thanks for the explaination. Sounds like the dealer was just looking for something to replace. The car never showed signs of smoking on startup, or while driving. No check engine light. I quess that my car is just one of those p-cars that has a high oil consumption rate? Everything else about the performance of the car is excellent. No other problems on this 26k mile car other then the high oil consumption. I wonder if anyone out there has been able to reduce their high rate of consumption by other means? Tom L 2002 C2

A bad oil seperator will not cause oil burning. It is fed by the crankcase pressure and simply seperates any solid oil in the crankcase fumes, cools the fumes and feeds them back into the throttlebody. If you are getting alot of blowby due to improper ring sealing, you can improve the ring's seal by doing the following. On a fully warm engine, take the car (in 2nd gear) to redline and remove your foot from the pedal. Do not press in the clutch...let the engine slow the car all the way back to about 2000 rpm. Repeat a few times and then drive normally. Do this a few times every day and you should see your oil consumption, if caused by the rings, become less.

A failed diaphragm inside the oil seperator will definately increase oil consumption. Before the oil is fully seperated itll get sucked back into the intake and burnt.

Even if evey internal part of the seperator was removed, you would not have oil going into the intake of any measureable amount unless you maybe had 10 quarts too much oil in the crankcase or were running the engine upside down. The only oil that can enter the seperator comes form the top of the block, above the level of oil. This allows crankcase gases to escape and be fed to the bottom half of the seperator where it is cooled by coolant flow. Near the top of the seperator is where the gasses (with minute amounts of solid oil) is sucked from on it's way to the intake. If the internals of the seperator failed, you would be mixing oil with water and water with oil. Failure of the bellows tube will cause external leakage. The seperator is simply a device to allow the crankcase to vent in a closed system. If you crankase if pumping oil into the seperator, you have severe engine problems. As a matter of fact, I bypass the seperator on my 99 and have.

Interesting...the Porsche mechanics spin on the oil seperator vs. oil consumption was that it was sending oil through the intake, therefore causing the engine to burn it off. This was evidently what PCNA was telling the mechanic. I told him that I would think if this were the case, I would show signs of smoking. I have never seen smoke on start up, or when following behind the car. I drive the car pretty hard, probably alot harder then the previous owner did. I have the feeling that the previous owner never really got on this car. He lived in the big city with nowhere to go. I have always thought it was a ring issue since it obviously burns oil and I don't see any smoke. Guess it's time to try the red line routine and see if it makes a difference. Tom L 2002 C2