603 belt tensioner
 

I replaced the 300SDL belt tensioner this afternoon. The manual calls for removing the fan, shroud and even the radiator on a 126(say what?) but I didn't have to. I removed the belt, upper shock bolt and spring, twisted the tensioner fully clockwise, removed the shock (the lower bolt just clears the water pump pulley), removed the idler pulley, then removed the tensioner. Installation was the reverse.

No idea what Omnifit 100 Orange is so I used the same gray RTV I used in the M103 tensioner bracket bolt that goes into the timing chain cavity.

I checked the archives and didn't see any reports of anyone having replaced a tensioner this way. The shock is still good (really stiff and solid bushings) and looks newer than anything else in the belt area, and the pulley was okay (makings of noise but no play). Since I can get to these bits without major surgery I'll wait for noise before I replace them.

Also replaced the AT cooler flex lines since the passenger side one was leaking at the hard line fitting. The fitting on the driver side is hidden by the engine oil cooler lines and is a major PITA to get to.

Now for the IP side cover leak...

Sixto
95 S420
87 300SDL
83 300SD ... $950, see cars forum

For some reason Mercedes likes to recommend that all the fan/shroud/etc. gear be removed when doing that kind of job. It was the same story when I replaced the vacuum pump on my 603 engine. All I needed to do was loosen the shroud and push it out of the way. Either they recommend removing all that stuff to save some of it from damage by less that careful mechanics or they are "rounding up" the standard rate charges a bit.

By the way, the side IP gasket is a breeze to replace, takes about 5 minutes. It's the others that are a bear.

Who sells the gasket for the IP?

Thanks,
Sixto
95 S420
87 300SDL
83 300SD ... $950, see cars forum

I got it at European motors in the city. They had to order it but it was not expensive, if I remember correctly about $3.

Sixto:

You're lucky, I couldn't get the shock bolt out, no way, no how. Ran into the fan pulley, so we pulled the fan. Had the tensioner spring off, too.

Why didn't Benz use that nice spring system on the M103?

Peter

I am attempting to replace the idler arm on my 1987 300TD this weekend. I was able to remove the belt without removing the fan. However, I cannot figure out what type of bolts are holding the idler arm and the pulley. The idler arm looks like a TOR-X type and I assume the pulley is 8mm allen. Do I need to remove the pulley before removing the arm?

If I cannot get the access I need, what size bolt holds the fan?

Thanks,


1987 300 TD 196Km
1987 300D 186Km
2001 CLK 430 Convertible 31Km

I am attempting to replace the idler arm on my 1987 300TD this weekend. I was able to remove the belt without removing the fan. However, I cannot figure out what type of bolts are holding the idler arm and the pulley. The idler arm looks like a TOR-X type and I assume the pulley is 8mm allen. Do I need to remove the pulley before removing the arm?

If I cannot get the access I need, what size bolt holds the fan?

Thanks,


1987 300 TD 196Km
1987 300D 186Km
2001 CLK 430 Convertible 31Km

The tensioner takes a 12mm hex bit through the pivot axis. There should be a cap covering the hex... uhh... socket? The idler pulley bolt takes a 5 or 6mm bit. Better to deal with it with the engine holding the tensioner for you.

Sixto
95 S420
87 300SDL
83 300SD ... $950, see cars forum

I took off the pulley with a 6mm allen wrench. No problem! I had trouble with the 12mm tensioner. I started with a pipe as a breaker bar which I ended up bending. I then used a rectangular x-section bar which broke it loose. It was tight, but I got it off and out.
I will see soon if I can put the new parts in without removing the fan.



1987 300D 186Km
1987 300TD 196Km
2001 CLK 430 Convertible 31Km