First off..the smog pump is removed (dont need it in central WI).
Second... when i would turn on the HVAC system, it would squeel. Turned it off... no problem. Well winter is coming up and heat is a must.
This weekend my goal was to fix the squeeling issue. I went to Autozone and got a new belt (Dayco 5060930/ 6PK2360), put it on, and now the sqeeling is much worse, even with the HVAC off.
I checked the tensioner with a 15mm socket before i installed the new belt and it seemed fine to me. The only issue that i see is that, when i try to turn the belt, i get about 1/2 to 3/4 turn on it now.
Does anyone know what could be causing this to happen? wrong size belt? bad tensioner? Im at a loss here...

Automatic tensioner by the way

If you have the M104 engine the idler pulley gets wore out.Easy fix.

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1999 w140, quit voting to old, and to old to fight, a god damned veteran, deutschland deutschland uber alles uber alles in der welt

OK thanks! I'll check that out. Seemed like it could be bad... didnt spin freely for an extended period of time.

Replaced the idler pulley. No change. Bought a smaller belt and will try that. Hope that works! The belt I had on it was 93". The new one is now 92.3". I will post my results after I get it installed this weekend.
how reliable is the water pump on the E320's?

IYAAYAS, as for the water pump check for leakage from the weep hole. With the accessory belt removed turn the water pump pulley and check for excess play. If you need a replacement water pump recommend buying a reconditioned water pump from your local MB dealer.

Belt is usually measured in mm. The Parts Department at your local MB dealer may be able to tell you the proper length belt with the air pump removed, or you can do a Search on this website. The belt shouldn't turn at all by hand if it's the proper length and the tensioner is functioning properly.

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Fred Hoelzle

Squealing issue solved! After a long time of screwing around. The proper belt size I found was 92.3 inches.
The previous owner installed the wrong size belt. Thanks douch!
thanks everyone for the input and possible causes for the squealing. Much appreciated!