Loose Fan Belt, symptoms?

Kemo · 11-24-2025, 07:05 AM

all,

i was at the track this weekend and my car was really bucking and missing a little bit but only under full throttle. If i were to ease into the rpms without going full on foot down, the problem seemed to be less noticeable. i also noted that my alternator belt seemed a bit loose and i could hear some squeaking on startup but it went away. i was able to drive and have fun but not really being able to accelerate at full potential. in any event, the belt eventually destroyed itself and i noted that the car did not like it at all with a big miss and a little backfire as i was coming off track. i was able to drive the car at low rpms to get on the trailer and did not overheat as i caught it real quick.

can a loose or failing belt, that may be slipping really bad, cause the car to misfire or run poorly?

Thanks!!

ant7 · ant7's Garage

yes, if the battery voltage was very low due to the alternator not charging.
Ant.

Quote:

Originally Posted by Kemo

all,

i was at the track this weekend and my car was really bucking and missing a little bit but only under full throttle. If i were to ease into the rpms without going full on foot down, the problem seemed to be less noticeable. i also noted that my alternator belt seemed a bit loose and i could hear some squeaking on startup but it went away. i was able to drive and have fun but not really being able to accelerate at full potential. in any event, the belt eventually destroyed itself and i noted that the car did not like it at all with a big miss and a little backfire as i was coming off track. i was able to drive the car at low rpms to get on the trailer and did not overheat as i caught it real quick.

can a loose or failing belt, that may be slipping really bad, cause the car to misfire or run poorly?

Thanks!!

RDM · RDM's Garage

Once you get into it, make sure you have all six alternator pulley shims installed, either inside or outside the pulley halves. I have a friend destroy his fan's keyway by not installing the unused ones on the outside of the outer pulley half.