About 2 months ago, the AC compressor burned up internally (red hot inside; guessing main bearing froze). The AC pulley seem to work fine with the belt running around it, but then the s-belt "snapped". I could see smoke coming from the hood, smell burning rubber, then I heard the s-belt snap (it looks as if someone cut it). What it looks like, the belt snapped inbetween the AC compressor pulley and the generator pulley. Aside from where the belt snapped, the belt looked fine.

What caused the belt to snap?

Aside from replacing the AC compressor and belt (of course), should I replace the AC pulley? What about the belt tensioner (the complete 'arm' or just the pully - ball bearing and wheel) ?

I'm not sure what other parts I should replace, since the truck was running fine without the AC compressor working (did not turn it on - so everything should work the same). I believe there is a small kit of things that I can buy with the compressor (i.e. dryer) - the stuff that should be replaced when the compressor is replaced - so I'll replace this stuff.

But there are little bits of rubber stuck in the generator and compressor pulley groves. I'm sure I have to clean the groves out, but do I need to get every little spec out?

 

I had my tensioners' pulley cut my belt. I think you have to buy the complete assembly( about $75.00)

 

Chances are your AC clutch locked up from the heat generated from the compressor getting red hot. Did you turn the AC on by mistake? What about the defrost? The defrost uses the AC, even in cold temps.

I would replace the AC compressor, dryer and expansion valve and go from there. The AC clutch will come already installed on the compressor, so you don't have to worry about that.

Next I would check all the other pulleys and see if they free wheel. Also check the bearings in the idler or tensioner pulley by grabbing the pulley and trying to wiggle it side to side on the shaft. There shouldn't be any movement.

One last thing... make sure the new AC compressor has the same amount of grooves in the pulley as the old one. If it doesn't, it'll eat your new belt.

 

Thanks for the info. I'll check those things out.

 

Yeap, A/C's will cycle on even with the switch off. It is to keep everything from seals to bearings with refrig. oil so they don't dry out. That is why cars with auto A/C systems run for so long without any issues.

 

Do a search on the over running alternator pulley, there is a tsb in Geno's garage make sure you have one on your truck..

 

Here's what I did.
After driving less than 1000 miles (after the A/C compressor burned up internally) it was the A/C pulley that froze up, which caused the belt to snap. (the related thread)
https://www.dieseltruckresource.com/...d.php?t=219212

Here’s what an A/C shop did.

Flushed the evaporator, condenser and lines (excluding the liquid line).
Replaced the A/C compressor, accumulator container (aka. receiver dryer), liquid line which had the built in fixed orifice tube (aka. expansion valve),

I replaced the belt tensioner even though is was okay – meaning the pulley still turned but you could feel that it was not rotating smoothly (it felt like it needed grease in the bearings). For a 5 yr old pulley, with 95k I decided to replace it just to be on the safe side.

I cleaned the alternator / generator pulley because when the belt snapped, there was a lot of rubber debris in the pulley grooves. Now, the new Gatorback belt would seat properly. (I previously had a Mopar belt, but I did hear the ‘chirp’ at shut-down. For now, the chirp is gone with the new Gatorback belt.)

Thank you all for your input.

 

I would also blow the rubber dust out of the alternator so it can cool properly.
Ted

 

Thanks for that tip. Everything seems to be running fine since I did not blow it out yet.