Turbo rebuild DIY kit: a good idea? Or use rebuilder/core exchange?
 

My '85 300d is spitting oil back out the exhaust system, enough that I think there is a fair amount of oil now in the muffler. The tailpipe is oily and it leaves a residue on the ground if it sits still running for a few minutes.

This sounds to me like the turbo seals. I know that a certain supplier sells a DIY rebuild kit (probably also available elsewhere, have not checked). However, recently I was told not to use the kit, as while it works in terms of the seals, the turbo has to be "rebalanced" following the rebuild or it won't last very long.

I came into Mercedes from the Volvo world and had Volvo turbos and I know people there have been DIY-ing their own rebuilds for years. This is the first I have heard about the balancing issue in either 'world', Benz diesel or Volvo gas.

Would appreciate input. I probably have a spare turbo lying in my pile that I would rebuild and install. Otherwise the option is to go with one of the big rebuilders, like Majestic Turbos or the others, for an exchange. Much more expensive, especially with the Canadian dollar currently tanked vs. the US dollar, but less trouble and a warranty....

Also if anyone has experience with a Canadian supplier, would be interested.

Thoughts?

I had my turbo rebuilt years ago by a local turbo specialty shop in Calgary, I would think a shop should be close to you? Yes our dollar sucks big time.

having a turbo apart was fine, it doesn't really have small parts. since they rarely fail a used one is always an option - coincidentally, i have a garrett to get rid of...

I've thought about rebuilding mine, never done it before. I do have some shaft play, need to check my exhaust for oil there...

My '83 300TD has 200K+ miles, and according to Bergsma, you should replace the shaft, and both the impeller and turbine when that happens. IF one does that, I must assume you wouldn't Need to rebalance it, as everything would be new and unworn?

On this sort of thing it depends on what is causing the problem.

It is possible for the groove that the Seal rides in to be worn to the point that a new seal will not seal or it will not last long. So before odering parts you could take the Turbo apart and see what is worn and what is not and decide from there.

This sort of thing also is really not a rebuild because no one is measuering the bearing clearances and so on they are just replacing with sock parts and hoping for the best.

In theory if you mark the Position of the Aluminum Compressor Wheel to the steel shaft and get it back on in the same positon the balance should be preserved. The Fly in the ointment is if any metal has been removed from either the Turbine Wheel or the Compressor Wheel that would change the balance of the parts.
Heavy deposits of crude can also interfere with the balance of the wheels.

Anoter problem with tanking the Turbo apart is that none of the various threads on this or other forums do they agree on the proceedure to torque the shaft nut to.

The above being said many people have had success chainging the Bearings and the Seals on the Turbos there is a few who did not get away with it.

There is another issue concerning the parts. USA made of China made parts. Lots of China made Parts on eBay. No one has really conclusivly said that the China ones fail early.

Also be aware that if the Turbo had ever been rebuilt before it is possible for there to be Bearings with undersized inside diameters and or oversized outside diameters.

As mentioned, as long as the shaft doesn't have deep wear grooves in it and there hasn't been any contact of the rotor assembly with the housings, I'd give it a try. Use an indexing mark on the compressor wheel to shaft for reassembly. DON'T scribe, punch, or scratch anything. These parts spin fast enough that a stress riser can cause a crack and then it can come apart! Ideally, yes it should be properly measured and rebalenced and stuff but a lot of people have gotten by without. I put an entirely different compressor wheel on my old Powerstroke without any other service, did it on the truck actually, drove a long time with no problems. YMMV. For the cost of having a shop do your turbo, you can probably upgrade to a newer more efficient turbo off something else for close to the same money.

For torque, you can use a torque wrench to take the compressor nut off and gradually bring the setting up higher till it breaks free. That will get you in the ballpark for what it should be torqued to if you can't find any data. (ask a turbo shop)