My engine is burning oil, I took the car to the dealership and they couldn't find any thing wrong and no PCV valve, but the oil is decreasing constantly, and I can't find any trace of oil under the car or on the engine.
My car has 174000 miles.
My car has an automatic transmission.
The dealer should have performed an oil consumption test if this was your stated concern to them. Audi's published allowable standard for oil consumption is up to 1 quart per every 1,200 miles. You didn't say how much your car consumes, but you can see that their standard allows for quite a bit. If you are changing your oil every 5,000 miles, you could be adding 4 quarts between oil changes without Audi considering it excessive. The oil being used in your engine should meet Audi/VW specifications. Note that the crankcase ventilation control valve has been a cause of excessive oil consumption in some Audi engines. Your crankcase breather system should've been checked, but you may want to have that looked at again. If you would like to have an independent mechanic run tests on your vehicle, a certified technician from YourMechanic can come to your home or office to diagnose your low oil issue and recommend a repair.
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