M103 belt tensioner and water pump brands
 

Yes I know, I can search the forum, but I have and reading through several threads I could not find a clear consensus or really much info on what brands to use for the belt tensioner and water pump.

This car has almost 200K on it

Belt tensioner:
My car has a Febi belt tensioner which was probably replaced not too long ago (but not sure of that) but seems to have failed. I cannot adjust the slack out of the belt with the adjustment rod which I just replaced.

I know these Febi tensioners are the cheapest option besides like Trucktec or Uro but it seems to me that they are probably not the best quality. I know Febi sometimes has different suppliers for the same part, so I really don't want to gamble with them but if they are fine please let me know, i have no clue how old the one is on my car.

I have seen two other brands which sound promising and have been referenced before:

Gates, apparently uses an INA pulley, $110-$140, may be a reboxed part

Litens, supposedly German made, uses an INA or LUK pulley, $150


Water pump:
I also found a Gates Water pump on ebay for $55 that is discounted for not having a box, and it again may be a reboxed part but does anyone know if it is a quality part? I know Gates belts and hoses are among the best, but have no clue on their other products. I am not sure if my water pump needs replacement yet but it looks to be original.

2 Recs
 

Sounds like you have the skinny on what's going on with most of the manufacturers. Your comments agree with what I've read on here. I just went thru a search for the same two parts recently for my '89 260. Here's what I bot.

Your Febi belt tensioner, as you surmised, is probably a re-box job of questionable quality. I looked at a lot of different manufacturers and as you noted there wasn't a consensus of who made a good belt tensioner. There were a number of members that said swallow hard and buy the OEM one and that's what I did. The bottom line was you don't want to be changing it every few thousand miles.

And for the water pump, I think I did buy a Gates W. P. And as I recall ,it was manufactured in Italy. I will have to go find the box and check for sure and come back to you.

The water pump was reasonably priced, like the one you mentioned on fleabay. The OEM belt tensioner was several hundred dollars, ouch! Again, I'll have to try an find the invoice. Hope this helps.

I think my water pump for my m103 was either Laso or Graf. The belt tensioner was stamped with MB logo so not sure who the manufacturer was.

w123fanman, recommend buying a reconditioned water pump from your local MB dealer. As you probably know, it's necessary to loosen the center bolt on the tensioner assembly a turn or two before turning the adjustment rod; otherwise, you will destroy the tensioner assembly. URO parts are inferior, recommend avoiding them ... you get what you pay for.

That's actually probably what destroyed my tensioner in the first place, I tried replacing the belt as if it was something like the OM602. Didn't go well. I didn't find out until later that the tensioner uses a rubber spring vs a metal one. I plan to put this one in, get it all set, and hopefully never touch it again as I think I can just remove the alternator.