Turbo Squeal

[d2dave]

I have just purchased an Isuzu County sight unseen from Perth. It arrived today.

The seller told me that the turbo started to make a chirping noise as he was driving it to the freight depot.

He said he checked the clamps on the hoses and all seemed ok.

It is more a squeal than a chirp.

The car has a boost gauge and the noise comes as soon as the needle on the gauge reads about one pound and if I back off the noise disappears as soon as boost drops.

As there is no boost when revving engine stationary, how do I find where this noise is coming from?

[shack]

It's a bit hard to diagnose.

You may be able to replicate by having a companion listen to the motor whilst loading it up riding the clutch, but that's a bit dodgy.

I'd try investigating visually for a start, check the compressor wheel for ANY imperfections, they don't need much to sound awful.

Are you sure it's coming from the engine bay? the Isuzu's I've been in are that violent I don't know how you'd pinpoint the origin, if you can hear it really clearly, check it's not the line running to the boost gauge.

[Bearman]

Could be anything from a loose clamp to a rooted turbo. Buyer beware!!

[Don 130]

The turbo on my 300TDI defender made those sort of noises. The turbo was shot. I changed it out, but a new core would probably have solved it. Pull the hose off it and see how much you can wriggle the spindle.

Don.

[C H T]

Check the turbo flange to exhaust manifold nuts - if the turbo is loose you will get a squealing noise as the exhaust gases escape past the mounting flange gasket. I had exactly this problem on my 4BD1T recently. I tightened the nuts and problem solved.

FWIW

C H T