mechno1

Anyone knows where is the PCV valve located? I can't remove oil cap when at idle and I was told that the PCV valve is probably bad.

a4-18t

On my A4 1.8T 2003 it is located under intake manifold towards back of the engine. You have to remove the coolant reservoir to see it. The first picture shows the opening where the PCV valve larger end (arrow) attaches, the second the PCV valve (arrow) and the pressure regulator valve for crankshaft housing ventilation. These two are frequently confused.

Removing PCV valve is a bit of pain if you stil have original Audi clamps, but you can do it with the screwdriver and long pliers. All you need to do is to gain access by unscrewing the coolant reservoir and moving it out of the site. Then you can reach the hoses from the side. Spray a little bit of PB Blaster or some penetrating liquid to help with removing the hoses off the PCV valve connections.

Good luck!

lyleswk

Good info below but why are you removing the oil cap while at idle?

ECS Tuning-Audi

There's really no problem with removing the oil cap at idle. This can often times help diagnose problems.

If at idle you can't remove it often times is because of a vacuum issue.

Jason

lyleswk

That is what I was fishing for, just wanted to make sure that is why the OP was doing it.