whistle on boost

[LandCruiser1978]

done nearly 4k in the 80 since i bought her and not had a problem.
However this week she has become slightly annoying .
Drive below 1800rpm and it's nice and normal as soon as you go above 1800rpm you start to get a whistling noise from the engine ..
Now i've checked the boost hose and it seems fine what else can i check?
Engine is standard apart from the egr piping being modded to not allow egr to work

1996 24v manual

 

[Towpack]

Look for cracks or splits in the pipe from the airbox to the turbo. A blowing or split exhaust on the front downpipe also gives this noise but will obviousy make the exhaust louder too.

 

[Cptsideways]

Check the small hoses that feed off the manifold to the fuel pump & boost sensors etc.

 

[frank rabbets]

I had exactly same problem on mine. Turned out that the flange on the turbo pipe had warped causing a slight gap where the gaskets go. This is the flange where the 4 studs hold the egr valves on. Air blowing through the gap made a squealing noise at about 1800 rpm on constant throttle opening. I removed the pipe and took the studs out of the flange and filed it flat. A bead of silicone on every surface when putting it all back together saved buying gaskets for all the parted joints. Been perfect ever since. If you have no egr valves you may still have a similar problem on this flange due to warping or poor sealing.

Frank

 

[LandCruiser1978]

Couldn't find any leaks ..

And today the whistle has stoped.
Now is this a good thing?

 

[LandCruiser1978]

Just to update this thread

Found what the problem was with this whistle .. one of the bolts for the EGR was missing ! (EGR Bolt closest to the bulkhead )
It must've just rattled out
Presume this was the cause of the noise
I don't know why it randomly stopped whistling but it did start again and then stopped .. Very strange

Since fitting a new bolt it is lovely and quiet (well as quiet as a cruiser can be )

 

[frank rabbets]

Told you! [ a fluke]

Same place as mine and the ss gasket was acting as a reed instrument. I did not have a missing bolt however so had to take manifold off and fioe it flat.

Glad it was so easy ,
Frank