late M104 belt tensioner on M103?
 

Is it possible to retrofit the late style M104 serpentine belt tensioner onto an M103?

I'm getting ready to swap a 3.0 M103 into a 190E and while I have the engine out, degreasing and replacing the water pump, hoses, etc...I was wondering if I could upgrade the belt tensioner to the simpler late style.

Anyone?

I don't think the late M104 tensioner works on a M103....the early 104 one does, but not the later version.

But I wonder if all that needs to be changed is the a/c compressor bracket?

Anyone?

babymog would know for sure, but I think I recall him saying that such a swap would not work.

Anyone?

In case anyone is wondering, this swap is very possible although with the expense, it may not be worth it to you.

Basically, you need the following:
- late M104 a/c bracket (A104 236 01 30)
- late spring loaded tensioner
- late tensioner pulley (104 200 10 70)
- late rear powersteering pump bracket
- and the big one...late a/c compressor and appropriately modifed hoses

I have everything but the compressor and hoses which I will most likely source used. If you don't want a/c, you can leave the compressor off and use a shorter belt.

So, to answer my own question, yes...the newer M104 spring loaded tensioner will bolt-on to an M103 engine with the above parts. Is it worth it? You'll have to decide that for yourself.

Seems like a lot of work/hassle/expense when the normal M103 tensioner seems to work just fine for the most part. I've had no issues with mine so far....

I agree but the first time you change the belt with the new style tensioner and then compare it to the old style and it may just seem worth it. LOL.

I'm doing all this testing with an engine out of the car, btw.

I'm still working on gettin the late '95 PS/AC/etc. to work on a 603, ... but can say that the late M104 tensioner assembly is an improvement over the 103/early104 tensioner.

Jeff:
What do you have left to do? Isn't it all plug and play (assuming you modify the a/c hose)?

The late (R134a) compressor is held at a different angle, wiring is different, plumbing is all different (aux. pump in a different place, heated washer bottle, etc.), fuel system different, the M104 cruise-control is completely different, wiring shut-off solenoid, throttle linkage from a 603 car, inner-firewall, exhaust, instrument cluster, ECU to control idle, .970 glow-plug relay/wiring, ... it needs to all work and look factory. I thought it'd be easy.

It'd be fairly easy if I wasn't worried about Cruise and A/C.

Oh...you're doing much, much more then a simple tensioner upgrade!

Yes sorry, it's a modified OM603 turbodiesel in a late-'95 E320.

Hobby cars can consume you.

Really old thread but has anyone actually done this?

I have a similar story, I have a 3.0L M103 to put into my 190E Sportline and for the sake of my sanity I want to put in the updated tensioner. I found a C280 in the yard that has the updated brackets and all, plus I have an AC hose crimper that'll allow me to customize the lines. The compressor on the 3.0L is shot and the compressor on my M103 is close to death and I don't have any compressors with less than 180K on them so I was thinking of buying a new compressor anyway as they are a pain to change in the car. Since a new Denso is $225, it's really not too bad cost wise. I'll spend about $70 or so on the brackets and hoses, new tensioner and pulley is about the same price as a new Febi tensioner which is a PITA to use and has already failed on me in less than a year.

I've done it on my wagon. I just used my old compressor with a hack at the rear bolt.