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Squeel from exhaust!!


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I have had my 300tdi 90 for about 4 yrs. In this time i have never driven it!! Bought as a cheap project (NOT) any way i rebuilt the engine and then replaced chassis and lots of other bits.

It is nearly ready for the MOT, i fired it up and all seems well, except at a certain RPM i get a squeel comming from the exhaust quite loud, above or below this point its fine.

Should i be worried? Anybody else have this? What could it be?

Im guessing at turbo but is this normal, everything is standard exhaust etc.

Thanks Graham.

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I have had my 300tdi 90 for about 4 yrs. In this time i have never driven it!! Bought as a cheap project (NOT) any way i rebuilt the engine and then replaced chassis and lots of other bits.

It is nearly ready for the MOT, i fired it up and all seems well, except at a certain RPM i get a squeel comming from the exhaust quite loud, above or below this point its fine.

Should i be worried? Anybody else have this? What could it be?

Im guessing at turbo but is this normal, everything is standard exhaust etc.

Thanks Graham.

Hi Graham,

This might sound silly but is the exhaust secured on its rubber hangers or is metal touching metal on the mounts Because I noticed after refitting my exhaust it gave a strange noise (not a squeal though) at a certain engine speed and it was because the exhaust was resonating against the mount as I hadnt fitted it properly on one of the rubber hangers

Well its worth a look anyway.

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Hi Graham,

This might sound silly but is the exhaust secured on its rubber hangers or is metal touching metal on the mounts Because I noticed after refitting my exhaust it gave a strange noise (not a squeal though) at a certain engine speed and it was because the exhaust was resonating against the mount as I hadnt fitted it properly on one of the rubber hangers

Well its worth a look anyway.

Yes they are all fine, but this is a definate squeel, first i thought it was a belt sliping, but defo from exhaust outlet.

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If you suspect the turbo, take off the pipe from air filter to turbo and then reach into turbo and give the turbine a wiggle with your fingers and see how much side to side play it has. The squeel may be the blades rubbing on the casing where the bearing is starting to go. Or it may just be corrosion on the turbo where it has been sitting idle.

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Lol, yep :)

Another thought would be to make a recording of the noise .... do it as a video and post it on YouTube then post a link in this thread .... easier than describing the noise :)

May well do that tomorrow, had lots of other stuff to try and sort today; electrics seem to have gone haywire and cant get anything to work at rear, and been setting up steering etc.

Jobs that i think will only take a few minutes to half an hour seem to take all day!!! Is it me?? ;)

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May well do that tomorrow, had lots of other stuff to try and sort today; electrics seem to have gone haywire and cant get anything to work at rear, and been setting up steering etc.

Jobs that i think will only take a few minutes to half an hour seem to take all day!!! Is it me?? ;)

I know the feeling: mot in sight and then another thing goes slightly wrong and its another week. I had this intermitant gremlin with my 90 and it was a shonky connection in the fuse box and lose earth.

Keep going! ;)

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I kinda think you've got a pressure-leak somewhere. Whether it's on the intake-side of the turbo or downstream on the exhaust it's hard to tell. But losing pressure through a leak is going to be losing you performance too.

--Tanuki

"Sir Henry, enfant-terrible of artistic communities the world over, has just finished his latest exhibition. Paintings were hung on the gallery walls for a short period then removed before the critics and public were allowed in to view the now-bare walls. He describes this as 'homeopathic art'."

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That sounds horrid! There also appears to be an absence of smoke which is odd...

But the noise at 0:45 odd sounds like almost the turbo is running without oil! That may not be the case but it certainly sounds of an appropriate frequency for compressor / turbine to be rubbing the housing... Have you looked in the compressor yet?

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If it were the turbo or air intake problem I guess that you would probably hear something from under the bonnet, seems strange to me that any front end problem would be transmitted as 'noise' out the back end. Just a theory but could it possibly be a loose baffle in the exhaust system or a peice of metal from a baffle stuck somewhere in the exhaust system deflecting the exhaust gasses causing this noise?

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It does smoke but only a small amount, and as said the squeal is only at a certain RPM.

Im pretty certain that nothing is in or broken inside the exhaust system, so...... i will check the turbo for oil and rotation.

As said earlier i have rebuilt the engine and it has not been run for more than 2hrs in total and thats stationary.

Oil pressure is good, on tickover 25-30 psi.

Anybody else got any other ideas or have heard this before?

Thanks again.

Graham

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As you've not long rebuilt the motor, how long would it take to pop the 2, 3 bolts that connect the rear section of exhuast and just rule out any baffles in the rearmost silencer?

I'd suggest a confirmation of oil flow through the turbo as the first step, are you certain its getting there, not a build up of crud in the galleries? perhaps cracking the drain off to make sure there's oil coming out of the turbo housing would be beneficial, but make sure there's someone to kill the engine PDQ, you dont want to dump all the oil and run dry!

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As you've not long rebuilt the motor, how long would it take to pop the 2, 3 bolts that connect the rear section of exhuast and just rule out any baffles in the rearmost silencer?

I'd suggest a confirmation of oil flow through the turbo as the first step, are you certain its getting there, not a build up of crud in the galleries? perhaps cracking the drain off to make sure there's oil coming out of the turbo housing would be beneficial, but make sure there's someone to kill the engine PDQ, you dont want to dump all the oil and run dry!

I was thinking about the exhaust removal last night, and the check on oil, thanks for confirming my thoughts.

Will have to try later as SWMBO has insisted she gets at least 1 day attention over this bank holiday!!!! :(

Still if weather turns nasty she will want to come home again, fingers crossed for bad weather then.

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I was thinking about the exhaust removal last night, and the check on oil, thanks for confirming my thoughts.

Will have to try later as SWMBO has insisted she gets at least 1 day attention over this bank holiday!!!! :(

Still if weather turns nasty she will want to come home again, fingers crossed for bad weather then.

Sounds like a bit of whistle on a sharp edge somewhere; I think the removal and try again a really good idea.

Nigel

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Thanks for all the input guys; finally took the back box off today and low and behold squeal has gone.

Nothing seams loose in the back box and nothing has come out yet, so will put it back on when exhaust cools and hopefully it will have gone.

Checked the turbo and oil and all seems fine there, retightened all air hoses again nothing loose.

Graham

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Well put back box on and squeal is back!!!

Will have to wait till after MOT now then will remove back box and have side or rear exit pipe.

Have seen one where it exits through body work at rear panel above crossmember on off side, as opposed to side exit through body.

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