P38A Diesel Turbo Squel

Lukas018 · Oct 17, 2020

Hi,

Was driving home last night and when accelerating/engine under load i get a loud squel noise and dies down when not under load.

No smoke when accelerating, runs and drives fine. Looked at all pipe and no noticeable splits. Run engine inlet hose off exhaust on still makes noise when revved.

Noise is coming from back of engine not front as suspected belt and pulleys but they seem fine.

Anyone know what it could be or what I could check please?

Ta

Henry_b · Oct 17, 2020

More than likely the vanes in the Turbo..

Take the inlet off and give the vanes a jiggle wif ya finger!

lynall · Oct 17, 2020

Exhaust manifold gasket leaking, hence the squeak/whistle as the engine starts to work.

Of course if could also be range rover speak for kill me now please

Lukas018 · Oct 17, 2020

Henry_b said:
More than likely the vanes in the Turbo..

Take the inlet off and give the vanes a jiggle wif ya finger!

Thanks mate, what am I looking for when checking vanes? Excessive movement?

Lukas018 · Oct 17, 2020

lynall said:
Exhaust manifold gasket leaking, hence the squeak/whistle as the engine starts to work.

Of course if could also be range rover speak for kill me now please

Thanks will check the nuts as put new gaskets on a month ago.

My RR is cursed tho

Henry_b · Oct 17, 2020

Lukas018 said:
Thanks mate, what am I looking for when checking vanes? Excessive movement?

Yep

brianp38dse · Oct 17, 2020

Lukas018 said:
Thanks mate, what am I looking for when checking vanes? Excessive movement?

Just dont do it when the engine is running

Lukas018 · Oct 17, 2020

Just the run with car without the turbo and exhaust manifold and whilst naturally loud noise the squealing went so can only assume turbo is at fault.

Vanes seem OK not moving around.

Mark Piercy · Oct 18, 2020

Check around the intercooler for hairline cracks and traces of oil misting.
There should be a tiny bit of play on the shaft in a cold turbo but not enough for the turbine to touch the casing around it. Try and see into it also for damage I. E broken fins.

dubbleRR · Oct 18, 2020

lynall said:
Exhaust manifold gasket leaking, hence the squeak/whistle as the engine starts to work.[/QUOTE I had that ,a leaking exhaust gasket squealed when accelerating hard ....Found some soot round the rear of the manifold ,The manifolds are also prone too cracking ,have a look for a hair line crack if uv got the manifold off .....RR..

brianp38dse · Oct 18, 2020

Is the oil supply to the turbo ok, as no oil = squeal
Thats how i diagnosed a duff oil pump on a bmw n47 engine that and it running ruff because the valve lifters were not pumping up

Lukas018 · Oct 18, 2020

Thanks all. I took the turbo off and looked fine in good nick.

The supply is fine as I found out when run engine with feed undone and it shout out.

Only thing could be were the exhaust spring nuts where loose. Not sure how tight they need to be as near impossible to get a torque wrench in there?

Intercooler is ok.

tomcat59alan · Oct 18, 2020

Lukas018 said:
Thanks all. I took the turbo off and looked fine in good nick.

The supply is fine as I found out when run engine with feed undone and it shout out.

Only thing could be were the exhaust spring nuts where loose. Not sure how tight they need to be as near impossible to get a torque wrench in there?

Intercooler is ok.

Is the steel "gasket" between the manifold and turbo ok?are the three bolts tight? 12mm bihex iirc.

Lukas018 · Oct 18, 2020

tomcat59alan said:
Is the steel "gasket" between the manifold and turbo ok?are the three bolts tight? 12mm bihex iirc.

Yeah the gasket is about 3 months old, bolts were done up to torque.

Lukas018 · Oct 18, 2020

A silly question, could it be a manual gearbox issue?

The noise was still there when clutch was down and disengaged just a long shot.

tomcat59alan · Oct 18, 2020

Lukas018 said:
A silly question, could it be a manual gearbox issue?

The noise was still there when clutch was down and disengaged just a long shot.

Dry release bearing?

Lukas018 · Oct 18, 2020

tomcat59alan said:
Dry release bearing?

Sorry for being stupid does this spin even when clutch is down?

Mark Piercy · Oct 18, 2020

Lukas018 said:
Sorry for being stupid does this spin even when clutch is down?

All the time, it sits up against the pressure plate. Normally will make a noise when not under pressure and goes quiet under pressure. Whereas a dual mass flywheel can make a noise when not under pressure and also under pressure.

Rubberknees · Oct 18, 2020

Just something to look for years ago I had a SD1 Rover with straight 6 engine which started squealing on gear changes and at certain position of throttle. Changed clutch ,thrust bearings plus other related bearings. Turned out to be blown gasket on inlet manifold sucking air, hence the whistle. Just a thought. Cost £1 for new gasket

Lukas018 · Oct 18, 2020

Mark Piercy said:
All the time, it sits up against the pressure plate. Normally will make a noise when not under pressure and goes quiet under pressure. Whereas a dual mass flywheel can make a noise when not under pressure and also under pressure.

Thanks Mark let's hope it's not that. Took turbo and manifold apart and started to reassemble it.

How tight do the spring nuts need to be where exhaust connects to turbo as I cannot get a torque wrench in there?

P38A Diesel Turbo Squel

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