M103: Tensioner & Serpentine belt question
 

Been wanting to install/change the belts & hoses on my '86 300SL for some time and finally started into it today. This is in conjunction of a good engine compartment detailing. I believe this car has the M103 engine.

Wasn't quit sure on how to remove the belt, so I loosened two bolts on the P/S pump mounts and the main bolt on the tensioner, then backed off the long, hollow bolt between the water pump & P/S pump. The tension slacked up and off came the belt. Did I do that right?

After I did that I got to thinking that maybe this tensioner isn't for the belt, but perhaps something to do with the timing chain or timing. Is the tensioner actuated by oil pressure?

Whats the correct reinstall procedure? There is a plastic indicator that points to some timing like marks on the tensioner. The indicator has moved during the cleaning.

Hope I didn't get something totally out of wack!

Thanks,
Cliff

Move the pointer to the minimum mark on the tensioner, then tighten the tensioner until the pointer reaches the maximum mark, or, until the serpentine belt is tight enough to satisfy you. Some people are hesitant to mess with the tensioner, but as long as the rubber bushing is ok, you shouldn't have any problems.

http://i179.photobucket.com/albums/w...d/HPIM3118.jpg

http://i179.photobucket.com/albums/w...d/HPIM3119.jpg

Thanks SLK for the tip.

Also found some good info by searching past threads.

Cliff

This is such a PITA tensioner. I'd like MB to come up with a replacement spring loaded tensioner, like other car manufacturers use.

I'll drink to that!

i share your sentiments.