Low Boost & whislting

[Mcflurry]

Hi all,

I'm trying to track down a boost leak on my '09 GU but having very little luck. I have a dawes + needle valve and have replaced all the hoses, removed the intercooler piping pre and post intercooler and found nothing. I've tried spraying the intake piping with soapy water and revving but found no bubbles. Turbo to manifold bolts are tights... and I don't have access to a compressor.

Any ideas what I can try next?

Cheers
Brad

[AB]

I'm sure you've done this but have you had a good inspection of the intercooler for any little cracks, etc?

[Mcflurry]

I had a go and didn't see anything obvious, a few small leaks on the intercooler but this change in performance was very sudden. I'm not sure whether an intercooler leak of this size would form so suddenly.. unless this has happened in the past?

[AB]

Not sure mate, unless the crack has suddenly gotten bigger somewhere.

That was just my first guess as I remember when our work car 3L had a crack on the IC. The performance wasn't that overly down but you could really hear the turbo whistle coming out of the crack on the IC though.

Almost like the IC amplified the sound.

Would be good if you could somehow bypass the IC for a quick test.

[mudski]

I had a go and didn't see anything obvious, a few small leaks on the intercooler but this change in performance was very sudden. I'm not sure whether an intercooler leak of this size would form so suddenly.. unless this has happened in the past?

Replace or repair the IC first I think then reassess. Other than this the exhaust manifold has possible warped or cracked.

[Touses]

Check your turbo pipes are tight on the turbo. Had this one a while back, similar symptoms.
Hard to track at idle. Only manifests at revs, was a lucky guess on mine.

[Lionel84]

I had a boost pressure line that wasn't tight from the intercooler to the boost pressure sender. The sender barb was thinner than the hose and let high pressure air out. It was whistling like a blower, and after I put a zip tie on it, I got back 2psi of boost.

[Mcflurry]

Thanks for all the messages guys, I read on here someone had an issue with their Dawes valve which caused this and sure enough... I pulled it out, gave it a clean and we're back!