1994 7.3 IDI Squealing/whirling Turbo

Jordan Akers

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So I have a 1994 7.3 Turbo swapped into a van chassis (1987 motorhome actually), and last fall the turbo started to make a whirling/squealing noise when you really giver throttle. I'm not eliminating the possibility that it could be a belt or something else, but it has always sounded like it's coming from the right hand side of the doghouse. I also pulled the doghouse off yesterday and went for a spin and it still sounds like as the turbo spools up, that is where the noise is coming from. The noise also disappears, as I let off the throttle (and the turbo PSI returns to 0). The noise isn't always the same pitch depending when I give it a lot of gas....

I took a video with the noise that I'll try upload somewhere if people think that'll help.

Last thing, I took the inflow air off yesterday (by the orange boot on my rig) and tried to wiggle the turbo fan shaft. It spun fine, but it felt like there was (very small, but observable) amount of play in the shaft up/down, left/right..

Any thoughts if you think it is the shaft? What to do / check next?

Video should be here:
https://drive.google.com/file/d/1f0xh6FdF8OpO-KSYdzsYAv_WFpkstBFF/view?usp=sharing
 

TNBrett

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I don’t really hear anything out of the ordinary, but that doesn’t mean a whole lot. I guess if you’re worried that there is excess play in the turbo, I would be looking for visual evidence of the compressor wheel running on the housing.


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IDIBRONCO

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I thought that I did hear the noise. It may have just been a trick of the light, but it almost looked like a haze of smoke coming out toward the passenger's side when the noise was there. Maybe it's an exhaust leak? These turbos will usually have a small amount of up and down play in the shaft. This is taken up by the oil going through there while the engine's running. If there's in and out play, then it's time to start thinking about a rebuild.
 

CBRF3

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Yeah the turbo isn't really making much noise outside of the norm from my experience but I did here a bit of slobbering like you might have a lack of compression on a few cylinders and this could be a injector issue aka bad injector pop pressure or a few dribbling injectors outside of that it sounded like a exhaust leak to me as IDIBRONCO pointed out and the play issue from side to side and up and down there will always be some of that its the nature of a floating journal bearing turbo it rides on a film of oil under pressure to make it hold centered when running / spinning if there is in and out play rebuild the turbo for sure as its a ticking time bomb.
 

Old Goat

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My Bro in Law just sent his turbo from his 94 to Classic Diesel Design last week for a rebuild. The impellers were starting to hit the inside of the housing. He didn`t hear any noise, he was fixing something and had the intake off and noticed the wear inside the housing.
He caught it just in time.

Like said above, it is a ticking time bomb. It wears enough and gets out of balance, metal pieces get sucked into the engine as they break off.


Goat
 

Jordan Akers

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Hey All, thanks for your thoughts! The squeal really doesn't come through as well in the video as it does in real life. It really hits in the first like 6 seconds of the video.

No in and out play on the wheel so I think (fingers crossed) the wheel is fine.. I'll check though.

@TNBrett I'll check the compressor wheels for any wear, I couldn't see any earlier, but it's in the hardest place to see / reach on the van chassis.

I'm going to prioritize investigating the potential exhaust leak and see if fixing that will make the sound stop. when I looked at the leak earlier, it appeared to be coming from where two pieces of the exhaust system joined... I think it is one of the y-tubes (could be getting the name wrong). I'll have to see if there is some kind of a washer in there.. Or do any of you know if there is a type of sealant that can help seal off that joint?


@CBRF3 - Any recommendations on dealing with the 'slobber'? A good ole' injector cleaner additive? I'd rather not replace a bunch of injectors or something worse...
 

typ4

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No washers in those joints, your play sounds normal, look for any leaks on the compressor side also. A exh manifold gasket will also make this sound. A customer of mine has sealed his slip joint up witn muffler cement and stove rope with a clamp around it. 4 months so far.


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CBRF3

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Hey All, thanks for your thoughts! The squeal really doesn't come through as well in the video as it does in real life. It really hits in the first like 6 seconds of the video.

No in and out play on the wheel so I think (fingers crossed) the wheel is fine.. I'll check though.

@TNBrett I'll check the compressor wheels for any wear, I couldn't see any earlier, but it's in the hardest place to see / reach on the van chassis.

I'm going to prioritize investigating the potential exhaust leak and see if fixing that will make the sound stop. when I looked at the leak earlier, it appeared to be coming from where two pieces of the exhaust system joined... I think it is one of the y-tubes (could be getting the name wrong). I'll have to see if there is some kind of a washer in there.. Or do any of you know if there is a type of sealant that can help seal off that joint?


@CBRF3 - Any recommendations on dealing with the 'slobber'? A good ole' injector cleaner additive? I'd rather not replace a bunch of injectors or something worse...


I advise a simple rebuild of injectors or atleast a pop test and calibration can get the pop tester for like $70 on amazon or ebay and it is simple to do the resetting of the pop pressure via reshimming the injector nozzles you want them within 50psi variation between them and OEM is 1750psi pop pressure i set mine to 1850psi and within a few thousand miles they drop to around 1775-1800 psi pop pressure hope this helps I disassemble my injector nozzles and put them in seperate plastic pill bottles with some diesel fuel in them around 1/2-3/4 way full of diesel and drop them into a heated ultrasonic cleaner for around 1-2 hrs then do the pop calibration and chirp test.

https://www.ebay.com/itm/282737030311?hash=item41d470b4a7:g:hrkAAOSwKBtfRNEZ



 
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SLC97SR5

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My buddy had a '94 IDI that would squeal under 12-15 psi. It was a leaky exhaust manifold. He snugged up the hardware and the noise stopped.
 

Jordan Akers

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Hey folks,

So I got in there and the rubber boots were all in great shape, so no hole there.

I did notice the two following issues:
1. There seems to be some kind of oil leaking within the turbo itself (see photo), since the blades are covered in black oily soot and so was the inside of the air intake.
2. There is a leak in the exhaust as it goes down to the passenger side exhaust manifold.. there doesn't seem to be any actual way of tightening these two pipes... any ideas? Or is this a muffler cement and hose clamp kind of deal? See other photos

Thanks!

IMG_1296.JPG IMG_1298.JPG IMG_1299.JPG
 

IDIBRONCO

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Yes there will be oil in the turbo but not from a leak. It's because the crankcase gasses are pulled out of the engine and into the intake where they are burned. If you take the lid off of the air cleaner on one of our engines without a turbo, you'll see an oily film inside the intake manifold for the same reason. The bottom of the air cleaner lid will also be the same way most of the time. Some people do different things to eliminate the oily intakes/turbos. Some will run a road draft tube which vents the gasses to the atmosphere. This works, but because of the design of our engines, it often looks like the truck is on fire at a stop light. The other solution is to run an oil catch can in the path of a longer, custom made gas vent hose. This works better than the road draft tube (in my opinion) except that you have to occasionally drain the oil out of the can or else it will fill up and stop doing it's job.
Judging by your pictures, it appears that you have an ATS 093 turbo. Congratulations. I think that this was the best turbo kit available for our trucks. This is at the place where the Y pipe and the up pipe meet. The exhaust pressure is what drives the turbo. This leak will result in a loss of pressure and will cause the turbo to have less force to drive it. Less drive pressure means that the turbo isn't performing to it's maximum potential (less boost). A common fix is muffler cement like you suggested. Another one is copper RTV. Whatever one of these you use, be sure to clean the ever loving crap out of the two pieces so that your sealer will be able to stick. Another fix is that IDIoit makes and sells a one piece, stainless steel replacement part that eliminates this joint so it can never leak.
 

Jordan Akers

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@IDIBRONCO

Thanks for all that intel! I'll just give it a try with the quicker solution using RTV or cement.. Which ever I have kicking around the shop.

Is there any problems that arise from the oily intake? Or is it more just an looks better kind of thing? I'm just trying to get back to understanding the squeal that has yet to reveal itself....
 

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