OM603 or OM 603A choices

Greetings all,

I posted this question on the P3 board also but figure there is probably more collective 463 diesel knowledge here. I appologize for the cross post for those of you who are on both boards - you know who you are :lol:

I have had a rear engine seal leak for some time on the 1990 300GD (463) with the OM 603 NA I-6 engine. It has slowly gotten worse over the last few years but has most recently become worse to the point that on long trips at prolonged highway speeds I end up with oil splatter on the back door. When I crawled under there to confirm that it was indeed oil and not ATF, I noticed that I now have a leak from the front seal.

So it seems it is time to do something about the seals. The front is a piece of cake compared to the rear which according to my manual begins with engine removal followed by crank removal. Hmmm. So whilst I have the engine out my mind wanders to the corner of the garage where I have a crated military surplus (condition unknown) turbo charged OM 603A from a Haaglunds SUSV.

So the question is, do I R&R the OM603 or rebuild the OM603A and put that in while I am at it. I am not adverse to a bit of monkeying around with fitting the engine or the exhaust as it is probably time to redo some of it on the truck anyway. But what else will require changing over? I think the air intake/filter will need some fiddling as well. I also have in a little crate next to the OM603A the transmission used in the SUSV. I am not sure of its ratios etc. It bears a 126 XXX number and is a four speed auto. So should I put that in as well or use the original 4sp auto in the truck now? (As an aside and explaination: The Army in Alaska has hundreds of the SUSV tracked vehicles so surplus bits come up for auction frequently (including entire vehicles). My wife drew the line at the entire SUSV so I settled for the drivetrain.) I understand the OM603A is not a common engine in the UK but maybe some continentals brought some over for you all to play with?

Given that the OM603A needs to be rebuilt (worse case since I don't know the status) and the OM603 has some 277400 KMS on the clock should I do something with it whilst it is out? It is running great, no smoke, easy starts in cold down to –10F last winter (even when I forget to turn the Espar on) and is getting 21-22 MPG.

Oh what to do? All this with a 57 Unimog 411 I am fitting with hydraulics for a snowblower and a 1982 406 with a huge Schmidt plow I am going over to ensure it is ready for snow time. And this is just a hobby?

Thanks for hearing me out and I appreciate any thoughts you smart folks might have.

Adam