Dodge Repair: AC compressor v-belt loosens/slips: 3.0L, dodge grand caravan, crank pulley

Question
1998 dodge grand caravan. 3.0 Engine

The v-belt running the A/C continues to loosen itself

I have tried numerous belts

It will last about a day and be loos again and then no A/C

The A/C pully turns freely

But upon tightening the nut it does not last

Thnak you


Ron

Answer
Hi Ron,
The lock nut on the axis of the idler pulley is supposed to be tightened to 40 foot pounds after you have set it up properly with the adjusting screw. The other possible reasons for the failure to hold tension would be that the compressor's mounting connections to the engine are loose, the belt tension is too loosely adjusted and starts to slip immediately (a new belt tension with a gauge should be 150 lbs, and a used belt 80 lbs; alternatively you set the tension so that when you push with 10 lbs of force on the point midway between the crank pulley and compressor pulley [underside of the belt 'run] that it deflects no more than 1/4"), or the idler pulley mounting is loose or the pulley adjustment mechanism is worn out. So between these possibilities you will find the reason for this problem.
Of course it may be the case that the compressor is binding up (you can't tell that by rotational feel unless you engage the compressor clutch (jump 12v to the dark blue/black wire at the clutch to engage it; or listen to the compressor when you ask for AC).
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Thanks,
Roland