Serpentine Belt Snapped

[ctd4stan]

Serpentine Belt "Snapped" / Split / Broke

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?

 

[ENafziger]

It sounds like a lot of extra "drag" was placed on the belt, either by the a/c or something else.

A similar thing happened to me when my Jacob's vacuum pump for the exhaust brake siezed. When the vacuum pump started pulling hard, the serpentine belt immediately started smoking, and almost caught on fire before I got the truck pulled over.

As I opened the hood, the belt snapped. There was melted rubber balls thrown everywhere, and melted in the pulley grooves as well. When my belt broke, it also snapped the belt tensioner, and sent it into the back of the radiator, snapping the fan shroud in the process.

If you have melted rubber in the pulleys, you need to find what was making the belt pull so hard and slip. You need to use a metal brush/etc to remove much of the embedded rubber so that the grooves in the belt can "seat" in the grooves of the pulleys. Inspect your tensioner arm/pulley as well for cracks.

--Eric

 

[BigPapa]

When your compressor seized up, the clutch was engaged causing the pulling to quit turning. The rest of the engine was still running which caused the belt to continue to turn and burnt it up on the A/C pulley. When you turn off the A/C the clutch disengages and the A/C pulley turns freely.



Scott

 

[ctd4stan]

I'll definitely check the idler, tensioner, and AC pulley's - or whatever else could cause the 'drag'. Because it has been 2 months since the AC went out and the truck was running just fine. Then something seized up and caused the belt to snap.



So, I'm guessing its one, two, or all 3 pulley's that caused the belt to snap.

 

[Motorhead]

The MOST important thing to be done is to make sure that the A/C system is THOROUGHLY flushed and the receiver drier changed. When a compressor goes south, it contaminates the A/C system with debris.

 

[ctd4stan]

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.turbodieselregister.com...flush-ac-system-when-compressor-goes-bad.html



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.

 

[brods]

Keep in mind when using the window defroster mode the ac compressor will run to dry the air. So if you hade the HVAC knob far enough left for the truck to think you wanted defog the windows..... bye bye belt.