My serpentine belt keeps coming off on my 454 Dually. The a/c is not working so the compressor is suspect. It started when I got the harmonic balancer was replaced. Everything has been replaced like tensioners, even brackets. What can be wrong?
Serpentine belt trouble
- Thread starter Andrew7
- Start date
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stutaeng
I'm Awesome
Well, if it started doing this when the harmonic balancer was replaced, why would you think it's the AC?
You can check alignment with a long straightedge. From the crank pulley, check against the various pulleys like alternator, PS, AC, etc.
You can check alignment with a long straightedge. From the crank pulley, check against the various pulleys like alternator, PS, AC, etc.
The a/c is not working so I thought the compressor could jam and throw the belt.
man-a-fre
I'm Awesome
Maybe the bearing on the ac pulley is locking up?
Most tensioners have markings to indicate their operating range of motion. Find out if your tensioner is within it's expected operating range. Make sure the tensioner pulley--along with all the other pulleys--are in good condition.
With the belt off, spin the A/C pulley. The bearing should feel smooth. Any roughness or play could be your root cause.
1. Crank to one side of the A/C pulley (upper or left side)
2. Crank to the other side of the A/C pulley (ower or right, so you're checking 180 degrees apart.)
3. A/C pulley to crank. Ideally, you check both sides of the crank pulley, just as above.)
Would be worth looking for cracked brackets, loose bolts, etc. on the various accessories--alternator, A/C compressor, PS, AIR pump, water pump, etc.
Are you sure you have the CORRECT BELT?
If the torsional damper was replaced because the bent crankshaft caused it's failure, you're in deep doo-doo. Let's hope the crank isn't bent. Does the new damper wobble? Does the tensioner arm jiggle?
With the belt off, spin the A/C pulley. The bearing should feel smooth. Any roughness or play could be your root cause.
Verify alignment of the belt. This is not easy, and it's more complex than most folks think. Your straightedge needs to prove alignment from the crankshaft pulley to the other pulleys, and ALSO FROM THE OTHER PULLEYS BACK TO THE CRANKSHAFT PULLEY. You MUST verify alignment both ways, because a pulley can seem to be aligned when in fact it's out of alignment in two different planes. It's a 3-D world, pulleys can be out of alignment by being angled top/bottom, left/right, or by being straight but too far forward/rearward, or any combination of errors. Verifying TWO pulleys--crank and A/C, for example--requires at least three tests of alignment.
1. Crank to one side of the A/C pulley (upper or left side)
2. Crank to the other side of the A/C pulley (ower or right, so you're checking 180 degrees apart.)
3. A/C pulley to crank. Ideally, you check both sides of the crank pulley, just as above.)
Would be worth looking for cracked brackets, loose bolts, etc. on the various accessories--alternator, A/C compressor, PS, AIR pump, water pump, etc.
Are you sure you have the CORRECT BELT?
Good question.
If the torsional damper was replaced because the bent crankshaft caused it's failure, you're in deep doo-doo. Let's hope the crank isn't bent. Does the new damper wobble? Does the tensioner arm jiggle?
Last edited:
Nad_Yvalhosert
I'm Awesome
So you say you have an R12 A/C system, that means 88-91. '92 was a transition year.
After the belt problem is fixed
After the winter is over
Then you can address the A/C system
First. Install the retrofit fittings and add a pound of R134a with Dye Just enough to potentially get the compressor pumping. Let her run 20 mins or so, to get the dye spread throughout the system. Check for leaks, repair as necessary. If you replace any parts, add 2 oz of new oil, plus the same amount of any you drain out.
Example: if you change the compressor, drain the old oil into a measuring cup. Say you get 1 oz. You'll add 3 oz into the new compressor
After the belt problem is fixed
After the winter is over
Then you can address the A/C system
First. Install the retrofit fittings and add a pound of R134a with Dye Just enough to potentially get the compressor pumping. Let her run 20 mins or so, to get the dye spread throughout the system. Check for leaks, repair as necessary. If you replace any parts, add 2 oz of new oil, plus the same amount of any you drain out.
Example: if you change the compressor, drain the old oil into a measuring cup. Say you get 1 oz. You'll add 3 oz into the new compressor
