My 2002 Porsche Carrera puts out a pretty big cloud of blue smoke when I start it up (especially after it's been sitting for more than a day or two.) I also find myself adding oil pretty frequently (about a quart every 500 miles or so.) I have been using Castro 10W-40 High Mileage fully synthetic oil. The car has 70K miles on it and this is the only issue I've had. What does this mean? Is there anything I can do to improve its oil consumption/the blue smoke? Could it be the AOS? Would really appreciate your input! Thank you!!!

 

Are you sure you are not overfilling the engine with oil?

If your car's engine is not equipped with a dipstick the only way you have of being sure the engine has the right amount of oil in it is to perform a proper oil drain and engine oil refill putting in a known and proper quantity of oil then checking the oil level using the electronic oil level system to confirm its reading agrees with the known amount of oil in the engine.

A once in a while cold start can have the engine smoking a brief amount of time: Really the smoking is ending almost as soon as it begins and should not be accompanied by any other untoward engine behavior.

If the oil level is ok smoking at startup, every startup, is not normal.

One possible cause can be a bad AOS (air/oil separator). This fails after a while (my experience after 3 of them is every 80K to 100K miles but your mileage may vary) and smoking at start (and when it really fails continuing after start) is a sign the AOS is bad.

The only solution is to replace the AOS. But you want to be sure the AOS is the cause of the smoking. It is a rather expensive job to have done if it is not necessary. And you want to get to the bottom of the smoking.

Not to put too fine a point on it but 10w-40 oil is not a multi-grade viscosity approved by Porsche. I don't think the oil plays a role in the smoking but Porsche only approves 0w-40, 5w-40, and one 5w-50 oil. Except for the 5w-50 oil there are a number of 0w-40 and 5w-40 approved oils to choose from.

Also, be aware that if you use your car in cold (-25C) temperatures Porsche calls for 0w-40 oil to be used to ensure proper lubrication of the engine at and after cold starts.

 

I think its your oil separator. Are there any cel lights? How do you know how much oil to keep adding, are you using the on board indicator? The amount of oil your adding is a lot.