I bought the car in 2021 with 6700 miles. Last oil change was at 14,000 miles. In between the purchase and my first oil change in Dec 2021, the oil light came on and I had to add a quart. Car has 20,000 miles now and it's asking me for more oil, indicating it is at minimum level.
My mechanic says it is common with this engine - anyone else dealing with this?

 

You should be changing your oil every 5k miles regardless of what the manual states.

Porsche publishes very liberal "acceptable oil consumption rates" if something like 1 qt every 600 miles, which saves them from replacing a bunch of motors that should probably be replaced.

 

Changing oil every 5k miles only for the Turbo? The non turbos are supposed to be 10k miles.

 

Anyone who is doing used oil analysis on their cars will tell you no oil lasts 10k miles. It shears to a lesser grade in as little as 3,000 miles (especially if it's Mobil 1) and even the better oils like Motul, Liqui-Moly, and Driven had have somebody their additive package used up by 5,000 miles and have turned from basic to acidic (TAN greater than TBN).

I finished oil analysis on every oil change on 8 cars and a wake boat and some of the cars actually need a lower mileage oil change than even 5,000 miles to maintain the viscosity and keep the metal wear and anti-friction additives in check - for example, my supercharged 997 needs it every 3,000 miles, my wife's 997 every 4,500.miles, etc.

 

I have an older (955) Cayenne Turbo and have been going crazy trying to fix the oil consumption.

The first thing I did was change and replace the oil cooler.

This helped reduce the oil consumption but recently dealing with a new problem: oily spark plug

I just changed out the valve cover gasket. Hoping this solves it.

If not, I'm selling and going electric. Very frustrating.

 

1 oily spark plug or all the plugs on that side of the motor. If one, it's likely a scored cylinder bore letting oil into the combustion chamber past the oil control ring, especially if the car ever lived in a cold climate. If it's all the plugs on the Driver's side, the PCV system vents the crankcase back to that side of the intake. Oil condenses into the intercooler on that side and when enough of it accumulates, starts getting sucked back into the intake, especially in high vacuum situations.

 

Make sure your running 5w40

Low Oil light to Full will take 2 Quarts. 1qt every 3k miles sounds normal.