How Much Play in the Turbo Shaft is OK?
 

Changing the scope of my original thread...

I've got about a 16th of an inch play left to right in my turbo shaft. Is that too much?

Also, there's a lot of caked on oil on the bottom half of the impeller housing. Is that ok?

There is a little oil residue on the inside lip of the turbo unit. If I wipe my finger I get not enough to drip, but a good amount. Is this ok?

Sorry
 

You had a good tread going, I wish you would not have left it and kept it going. But anyway, I think the "about 1/16 end play" is too much, but that is all I know. I don't have much experience on turbo failure. Was you "U" tube mounted properly, and on good and tight? I'll wait for more answers also.

A little bit of oil residue is normal.

I just checked it again, I don't think it's that much (a 16th) but I know it is more than a few thousandths. I still sortof wonder if the turbo could be the cause of the blue smoke but I don't know. Is there a way to diagnose that as the problem. I suppose removing the turbo from the intake could be one way to check it but that seems awfull time consuming. Is there a quick way to get the turbo off to let the engine just breathe without the turbo being there to inject oil. That would tell me right away if that's the prob.

If I recall correctly the bearing for the turbo is a film of oil.. so perhaps you are just feeling that small tolerence

Removing the turbo is not trivial....
 

...but you can remove the cross-over pipe between the turbo and the intake manifold. That will convert the engine into NA (Normally Aspirated). You should rig up some kind of air filter so you don't suck too much crud into the engine.

The slop in your turbo doesn't sound excessive from what I've read, but I don't have any numbers. We need input from someone with more experience.

Which car are we talking about? Sounds like you're talking about the 87 since the 617 has no crossover pipe.

Good point. Thought it was the '87.

He's got 2 diesels in his sig and I'm assuming it's 80 300SD because of "The new project" on the end.

Sorry guys... I didn't mean to make you have to troubleshoot on which car I'm fixing LOL :)

It is my 617 that I'm working on here.

I think if I pull the turbo off of the intake, I'd be able to eliminate that option as my oil in combustion (blue smoke) problem. But I'm afraid to mess with it. I'd assume I have to take it off to separate it from the intake manifold. I'm just looking for a turbo oil leak out of the question on diagnosing my blue smoke problem. The reason I even question it is that there is oil on the outside of the turbo housing.

1. Turbo shaft play of less than 1/16 inch side-to-side sounds okay. Front-to-back (in-out) play is more worrisome. The shaft rides on oil bearings, which have an outer diameter slightly smaller than the inner diameter of the races in which they fit; the gap is filled with oil when the engine is running. With the engine off, a small amount of side-to-side play is normal. (Obviously, you can't check play with the engine running; you'll lose your fingers.) Here's a photo of the front oil bearing in a Garrett T3 turbo from an OM617 In this photo the bearing is shown halfway out of the race.

2. I don't see how you can disconnect the turbo from the intake manifold and still safely get intake air from the air filter to the manifold. With this engine/turbo design, 100% of the intake air (excluding that which passes through the EGR valve) goes through the turbo at all times.

3. Unless you have significant front-to-back play in the turbo shaft, the likely source of oil in your intake system is not the turbo, but the air filter housing. Oil particles in the blowby gas from the valve cover are supposed to be collected by the separator in the air filter housing and drained back down to the oil pan. But the separator often does not work well, allowing oil to flow into the housing, onto the air filter, and into the U-tube. And drain holes at the bottom of the air filter housing allow this oil to drip down onto the turbo and other parts of the engine. If you remove the lid of the filter housing, is there a pool of oil sitting in the bottom? Is the filter wet with oil?

Good pic. Thanks for that. I talked to a 60 something year old MB mechanic today who's doing a recal on my other MB's trap oxidizer and he said the same thing about the slop. He said it floats on a film of oil so some play is proper. I'll check out the oil in air filter.