Whistle / squeek / vibration noise

Got one coming from the engine , I think I've narrowed it down to the turbo area but I'm not absolutely positive.

It's only obvious at certain rev ranges, when I'm changing up or down, or peculiarly at around 30 mph in 4th, if the engine is having to work rather than coast.

Any ideas or comments would be much appreciated as at the moment it's got me really scratching my head.

It's difficult to replicate the sound whilst stationary with the bonnet up but it is possible, this is how I managed to narrow it down to the turbo area.

2 things which spring to mind on this is the vibration and sqeak, and thats the bearings in the turbo, you could take the end of the turbo off and inspect the steel fins inside for free play in this case there shouldnt be any. the whistling noise could be mistaken for the sqeaking.

Done that , doesn't seem to be any play in the fins.

Yeah the noise really is difficult to identify, can't really say wether it's a squeek, whistle or vibration. Sometimes it sounds like one and at other times it sounds like another.

are the pipes tight? this will cause a whistling noise if they are loose,you could try reving engine up whilst under the bonnet and holding the pipes at the same time

I did try spraying a fine mist around the area whilst revving the engine, there didn't seem to be any obvious leaks, I'll give it another go whilst holding them.

I'll get back to you later, off to work now. Cheers.

While you are about it check for full flow OIL to the turbo.

STOP the engine.

Take off the pipe that leads oil to the top of the turbo.

Pull the STOP wire off the Injection pump so the engine does not start. TD5 you've got a problem. Get a friend to do the IGN KEY for the next bit so he can STOP it smartish.

Put a container at the end of the turbo oil feed pipe you just took off to catch the oil and turn the engine over on the starter. Oil should come out that pipe pretty briskly. Like a good steaedy flow.

If so, put the pipe back, and replace the STOP wire.

If no oil comes out the pipe, the turbo bearings are running dry and may be wrecked. And there's a lube problem in the engine.

If that checks out OK, make sure the manifolds are all bolted on tight, and starting from the turbo outlet, check every single hose, joint and hose clip to make sure there can't be any air leak.

Turbo pressure is quite high - 15 psi is common and that is enough to blow up tyres fit to drive on. So any air leak can make a lot of noise, as the turbo is pumping a whole lot of air.

CharlesY

Cheers for that CharlesY, I'll have a look first thing in the morning and get back to you.

Erm, are you sure it aint the prop shaft UJ's jus starting to go? Well, one of them.

sounds like a good bet there boydy

there is only one wire on the injection pump isnt there ?

G-man said:

sounds like a good bet there boydy

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I know what you're saying G-man but it would'nt explain how I still get the noise with the car static.

Try removing the drive belt ,and run the engine ,this will rule out Alternator ,water
pump and belt tension idler and pulleys . It will help narrow the problem down.

had similar problem mick a nick said turbo. took drive belt off .noise gone. spin water pump by hand it sounded hoberal

Well that's a few more ideas to have a go at cheers all.

Thanks for all the input guys.

Think I've finally sorted it, after trying all the suggestions it all boiled down to a bracket at the bottom of the exhaust vibrating occasionally against the engine mount.

Believe it or not it was only just touching it, and at certain engine revs it vibrated up and down enough to give off this high pitched squeak.

At one point i thought I'd got two separate noises, it really sounded like something serious. Certainly a weight off.

If its a TD5 it may be the centrifuge filter making the whistle noise ????
Mine does as it spins up and down depending on engine revs.

Shifty1962 said:

If its a TD5 it may be the centrifuge filter making the whistle noise ????
Mine does as it spins up and down depending on engine revs.

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No it's a TDI