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Crankshaft Pulley

CapitalTruck

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CapitalTruck Senior Enthusiast

CapitalTruck

Posted
Posted

I just put new belts and tensioners on my truck. On the A/C belt the tensioner is working overtime (it moves quite a bit). I'm wondering if this isn't due possibly to a loose crankshaft pulley. When I see it turning it doesn't look "true". Does this happen? Is tightening it as easy as it looks? (just tightening the nut in the middle of the pulley)?

txab Senior Enthusiast

txab

Posted
Posted

Your actually talking about the Harmonic Balancer. I doubt if it is loose. You can check it to be sure though. If you click the link I provided you can see how a HB is put together. If it really is not running true you may have a problem with the balancer

 

 

Found a thread that I had seen before that has a video of a member's HB running. You might read through it.

 

http://www.gm-trucks.com/forums/index.php?showtopic=100613

C. Charles Hahn Senior Enthusiast

C. Charles Hahn

Posted
Posted

With the age and mileage of your truck, I'd venture a guess that the tensioner is probably bad. I had a tensioner go bad on an S10 Blazer I had several years back with the 4.3L Vortec, and it exhibited similar symptoms. That's where I'd look first, as it's a far cheaper fix than a balancer issue, and a more common wear item.

CapitalTruck Senior Enthusiast

CapitalTruck

Posted
  • Author
Posted

This (seemingly) excessive tensioner movement IS on the new tensioner. Good to know about the harmonic balancer, this is something I never was even aware of (that it even existed). From the other threads listed I guess I will just leave mine alone (the last belt made it 120k without a failure, with new tensioners and idler pulley the new ones should also I reckon). Thanks for the info.

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