Audi all of a sudden started burning oil

[skidtank]

My Q7 with 3.6L just started smoking and using oil. Replaced valve cover with new PCV valve. Still using oil. Took intake hose off and there was oil in it. Took hose off air box out of PCV but it was not blowing oil. In another forum someone said I could have a cracked head. Could it be something else. Car has 160,000 miles on it.

 

[obi_waynne]

It could be the head gasket leaking. Get a compression test done and it might help you track down where the problem is. It'll be the gasket, piston rings or valve seals in most cases but a cracked head is a possibility. Running an oil flush through and good quality oil sometimes restores the oil control rings ability to scrape away the oil on the stroke if it has got clogged and gummed up.

 

[skidtank]

Thanks for the info. I'll try putting a oil additive through it and will get a compression test on all the cylinders. How hard is it to swap and engine in one of these cars? I can buy a used engine with 135k miles on it pretty reasonable.

 

[obi_waynne]

The worst thing is that pipes, wires and connectors tend to break so be very careful and assume everything is brittle and fragile. Other than that it is a fairly easy job (for a reasonably competent mechanic), sometimes swapping the sensors from the old engine to the new will be required it depends on the new engine year and version and how the ECU is setup.

 

[skidtank]

Yes, I found out the hard way when I was changing the PCV Valve about the brittle piping. The plastic they use for the connectors does not last very well and of course to replace some of them is expensive. Again, thanks for the info.