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Matt
Matt, Mechanical Engineer
Category: Audi
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Experience:  BEng hons Mech engineering, in auto industry 22 years
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I've got an Audi a4 avant Quattro 170. After running for little

Resolved Question:

I've got an Audi a4 avant Quattro 170. After running for little while it produces some blueish smoke and there is an oily smell inside the car.
Submitted: 2 years ago.
Category: Audi
Expert:  Matt replied 2 years ago.
Hello

The first thing I'd check is the crankcase pressure relief valve (PCV) these are sprung loaded and are only meant to 'burp' excess pressure every now and then. The exiting gas is piped back to the inlet , however should the valve stick open then the engine tends to suck the air out of the crankcase all the time and this carrys oil over with it.

If you remove the air intake pipe and look inside where the crankcase breather is plumbed in you may find evidence of oil.

If you do find oil replace the valve. If this is all OK then its possible that the valve stem seals are past their best and are drip-feeding oil into the intake. These can be replaced without removing the head by a competent garage in half a day or so

an engine flush may also help if you've got a sticking oil scraper ring so its worth a go, as for the oil if you go up a grade / use slightly thicker oil then this is less readily drawn into gaps and less likely to be burnt off
Matt, Mechanical Engineer
Category: Audi
Satisfied Customers: 20778
Experience: BEng hons Mech engineering, in auto industry 22 years
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