PCV test - clarification

[BigA91]

So just testing bits and bobs prior to my remap. I've just done the dipstick test and my car was running rough and the PCV was whistling. Does this mean the PCV is facked?

[beetie]

Sure that means it's okay

[BigA91]

So why does it whistle lol? I thought if it whistles, it's gone ?

[schmidt_vr6]

The other way to test the PCV is, Start the car and try to open the Oil Cap (where you pour oil in from). If the PCV is good. The cap will simply not open or even turn as it is building with pressure.

If it opens then you have a Knackered PCV.

[schmidt_vr6]

Also when I had a Knackered PCV on my car. The revs would Hunt on idle. It did not matter if the engine was hot or cold. And you could hear the engine noise whilst it was hunting too

[Pesky jones]

funny, my car is in the garage at the moment and they told me the breather valve needs replacing because when they try to take the oil cap off, it is sucked in. You'd think a garage that advertises as VW audi specialist would know there stuff...

[Dan_FR]

It will whistle as its sucking in air through the dipstick hole or engine filler cap hole that is then going through the breather system and in to the intake, either directly in to the manifold when off boost (vacuum), or through the rear breather in to the side of the turbo when on boost.

General rule of thumb - if it idles nicely until you pull the dipstick out, or remove the engine filler cap, and idles terribly and tries to stall when removed, then it's ok (obviously the filler cap having a larger difference due to the size of the 'leak' you are introducing)

[Pesky jones]

What revs does a healthy engine idle at? When I first start the car, in P, then it will sit above 1000, but then after a while and if put it in D then it drops to about 700.

[r5gtt]

What revs does a healthy engine idle at? When I first start the car, in P, then it will sit above 1000, but then after a while and if put it in D then it drops to about 700.

That's correct.

[Pesky jones]

yay

[BigA91]

It's fine then I suppose lol. Just did a 85 mile trip through country roads to AKS tuning and it barely even drank £10. I suppose if it is faulty, Niki will pick it up on the mapping session. Cheers guys!

[Mrstridey]

If its not already been sorted -

when you key off have a buddy listen to the engine. if it blows back/hisses when you switch off its dead!

[r5gtt]

I've literally got out my car and took the dipstick out and the cars hissed and spluttered and bit confirming all is well with the pcv although mine is new