Checking a turbo's health

I have a chance to get a turbo off another 300SDL as I am afraid mine is slowly but surely failing. I have to check if it's a KKK or Garett first, but how can I check besides the shaft play, the turbo's health.

I crawled underneath my car again yesterday and there is a good amount of oil on the underside of my turbo, and I don't think it's leaking from anywhere above it, is this a hint? The car does not leak alot of oil.

Also, how difficult is it to R&R a turbo in this car. It looked pretty straightfoward to me, only thing I am really concerned with is those bolts that got red hot and cooled a million times.

I had a 79 SD for years.. Sold it to a friend some time ago and still do the work on it.. And have had turbo's several other cars and trucks.. In general I have found that oil on the out side comes from external leaks.. On the Mercedes turbo its often the oil line thats under pressure comming into the turbo .. the gaskets dry out .. and on the line that drops the oil back to the pan. Its kind goffy setup but it works.. If you look at it you will see its two pieces ... one slides over the other with an o ring to seal them.. Over time these dry out... and it may leak at the top seal, O-Ring or at the bottom seal that goes into the pan area..the cost of these gaskets and seals are little and they can be replaced with the turbo on the car..

As far as leaks on the inside of the turbo.. When a seal goes it will dump so much oil into the engine that it will smoke so bad that you will know you have a problem..

As far as replacing the turbo.. its straight forward but some of the bolts may give you a problem because of rust...

However all that said.. If you get a chance to pick up an extra turbo.. Why not.. If its cheap.. It can't hurt..

Ken

I know Garret made the turbos on the 617s, and KKK makes trubos for Porsche, do not know whether that are OEM on a Merc.