I have a wonderful 82 300TD named Blu. Engine runs great, however when excelerating at highway speed, or going up hills, I get this whinning squaling sound that sounds like the turbo kicking in. It really sounds like a belt squealing.

I know there has to be another thread of this but if you search on 'Turbo' seems to be a highly used word, and 'turbo noise' got me a thread where it was the air tube, but their description of their noise seems different than mine. I also don't know what the turbo looks like exactly.

I will point out that the rubber mounts the air filter sits on are shot, and I get blow by in the air filter.

Expect that very little has been maintained as far as turbo hoses. Should that be the first place I look?

Why wouldnt you check your belts?

because it only happens at higher speeds or acceleration at high speeds, it seems to only happen when the turbo kicks in. But need to change the belt on principle anyway, or at least should have a spare in the car at all times.

Thanks I'll try that.

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1982 300TD, Rescued from rusting away on Martha's Vinyard, roaming the highways again, this time with a saggy bottom... No SLS

If it is indeed your turbo making the noise that means the bearings are shot and needs rebuilt. Keep running it that way and it will eventually self distruct and give your engine a shot or two of metal fragments.

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81 300SD daily driver/project
86 420SEL (sold)
85 380SE(in the graveyard)

The belt on my car only squeeked at higher RPM's, it went away after a couple miles though. You might check for a pin hole on the pressure side of the turbo. Im not sure what the intake tubes look like my car doesnt have a turbo.

Also, for your engines safety, it would probably be a good idea to pull the intake tube off the turbo and check for axial and end play on the spool inside the intake housing. It should spin freely and have very very very little movement either up and down or in and out. Take a peek in there and make sure everything looks good, no chips missing or bent fins.

You should also take the pressure side off and check for oil residue.. If there is liquid oil buildup then you have a problem.. if its minimal it probably ok.

I think you are right, it's probably the bearing(s). It started in Atlanta and has slowly gotten louder, I'm in Provincetown MA.

Whenever it makes the noise I back off of it. I'm assuming that I can buy bearings and rebuild it myself, or is this something that takes special tools and machines? I just searched and it seems straight forward... but am confussed if I have to have it professionally balanced?

Turbo City has this rebuild kit
http://www.turbocity.com/product_info.php?cPath=15_20&products_id=166

I'll check out allpartsexpress.com too! If I'm interneting an order would like to use the forums store if possible.

Thanks
Matthew

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1982 300TD, Rescued from rusting away on Martha's Vinyard, roaming the highways again, this time with a saggy bottom... No SLS

The last time the turbo rebuild was discussed it sounded pretty easy and relatively cheap to do...
But your description of " when the turbo kicks in " really does not fit the physics...
But the faster those belts are spinning initially the better chance further acceleration would cause them to squeal....
If it sounds like a duck , quacks like a duck, etc.... check or replace your belts first....
For a quick check only.... spray some of that belt stickum on the belts right after the noise has happened and test again... but that stuff is not the cure... replacing or adjusting the tension on the belts is the proper cure.

Wow first of all thanks so much for everyones 2cents!

My game plan for tomorow is to take the air intake filter housing thinging off. I have to check on the type of ruber screw mounts that are now missing that used to support the thing, then I will finger around the turbo and see if there is any play. If there is play it will get rebuilt and I will replace my belt and use old as spare. If there isn't any play and all looks good then I will just replace belt and use old as spare.

Hopefully it's the belt. I don't seem to have any of the other issues on the turbo rebuild discussion lists. I ony loose a quart of oil every 2000 miles, have plenty of power. I do have 265,000 Blu miles (Blu miles are that the odometer stops working above 50 miles an hour, it only clocks the around town miles). I really should stop looking for things to be wrong with this car 265,000 miles on an 82 Mercedes Diesel is just breaking it in.

I'll post tomorrow about what I find.

Thanks
Mattew

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1982 300TD, Rescued from rusting away on Martha's Vinyard, roaming the highways again, this time with a saggy bottom... No SLS

It does sound like you are looking for an excuse to open up the turbo...nothing wrong with that per se... but checking the belts is the logical cheap easy action to take first...
Your turbo " kicks In " at a much lower engine rpm than you think it does... so this whole image of being out on the road going fast and then it " kicking IN " does not fit the physics... and thus points to other sources of the noise...
If your turbo, spinning at up to 100,000 plus rpms did make a noise like that it would not make it very long.... it would have to be lacking in oil....and by the time it got to that stage would be very short on life....
Be sure you have whatever gaskets and bolts you are going to need to get this stuff back together... LOL

When turbo bearings go bad they start to scream just like a belt. They only start screaming when they get under boost.

I think what he means by kicking in is when it starts devoloping boost, which should be around 2000RPM? The turbo is spinning even at idle but not very fast and with no load.

I had a bearing go in a Chrysler Conquest turbo, sounded just like a belt in the beginning. Once it started getting worse it was really obvious it was the turbo.

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81 300SD daily driver/project
86 420SEL (sold)
85 380SE(in the graveyard)

when my turbo started going bad i was greeted with pinging noises of the compressor wheel banging against the housing at first i though the bearing on my new alternator had failed. even with that it would quiet down once it got into boost, but not all turbos fail equally. if it is screaming then I would check the oil supply.

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'81 300D - swapped to a 617.951 turbo motor with a 150 amp alt.

Yes, So his : " however when excelerating at highway speed, or going up hills," statement caused me to believe that the turbo was under load well before the squealing happens....
If a diesel MB turbo goes bad and is replaced.... the oil supply to the bearings needs to be corrected when the rebuilt unit is installed... the bearings are usually just the final symptom... the lack of sufficient oil being the problem.

The bearings will just wear out, even with proper oil. Think about how many revolutions that thing has made at 200k+ miles. In the gasser world, a turbo is considered worn out at 80k or so. A diesel should be no different, its still spinning the same rpm's pushing the same pressure.

Definitely agree with you that the oil supply needs checked and corrected if a problem. Last thing I would want is a new turbo with no oil.

Also agree that checking the belts should be done first, as its much easier and cheaper.

Just trying to inject some of my turbo knowledge since the OP stated he thought it was turbo related.

Thecorrupterx, seen them go that way too. 94 ford IDI. The owner still hasn't changed the turbo and it now develops 0 boost.

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81 300SD daily driver/project
86 420SEL (sold)
85 380SE(in the graveyard)

I agree with every point you made... except this one... the difference is that diesel exhaust temperature is much lower than a gasser... and so keeping those bearings and that oil from cooking is much easier. Many gassers have to have aux pumps and coolers which keep the oil circulating after the engine shuts down for this same reason.