Hi there,
I have a 93 f150 2wd with the 4.9l I6.. My serpentine belt keeps shredding, really fast ( within 10 miles of installing). I replaced the tensioner, checked all pulleys for straightness and still doing it. I am at a loss here...any thoughts? I have 153k on the engine..the belt shreds from the engine front side. I have looked at the engine run and see the belt becoming slowly frayed but cannot figure out what is actually causing it..
Any help would really be appreciated before I take it to the mechanic..
Cheers!

 

Is the belt riding in the center of the pulleys, or is it hanging off the edge of them? Are there any burrs or chips or rough spots on the pulleys (carefully inspect the V grooves on the crankshaft/alternator/air con pulleys)?

 

Check if one of the bearings is bad the pulley will wobble

 

Check your idler pulley, too. They have a strange habit of seemingly free-spinning, but will have slight hang ups when they're about to go south.....

Roger

 

Pull the belt off, or if it already removed itself, stick your hand down and shake the pulleys. If they have any movement that isn't just spinning on bearings, that's likely what's shredding the belt.

 

I followed your advice and found that the water pulley pump is pulling the belt forward. It is shaky too I found after removing the belt and trying to move it. So I guess a water pump replacement is in order... should I be paying attention to something else because of what i found?

 

You gonna replace the pump yourself? Whatever you do, make sure the coolant gets flushed out and drained from the engine block (not just from the radiator) and refilled with conventional green antifreeze (Zerex "original formula" from NAPA, or O'Reilly "conventional green"). NOT that universal antifreeze that's a paler green color; it just gets gunky pretty quick. It's advisable to replace all radiator and heater hoses and the thermostat while you're at it.

 

yep, will do this myself this week end. i was planning of replacing the thermostat and all fluids. I'll check the hoses too while I am it.