Idler Pulley Bounce and Dimming Lights


Jun 13, 2023
Richardson, Texas
Is this too much bounce for the idler pulley? I am seeing the lights flicker and dim rhythmically so I wonder if this might be the culprit or help diagnose what’s wrong
My crystal ball must not be working as I can’t see how much bounce you have, but regardless the idler pulley should not bounce… time for a new one. Your belt is more then likely slipping which could be causing your issue.
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Should I replace just the pulley or the entire tensioner too?

I'm wondering is the tension adjustable? Asides from the bouncing, it's completely silent

It’s the tensioner that is bad, which is allowing it to bounce.

I don’t believe there is anyway to adjust it. I would replace the whole assembly. I replaced mine a few years back, I went with a mopar one, but I’m not sure if they are still available, worth a look. If not just get a quality replacement one.

You use a 1/2 drive ratchet to release the tension to remove belt. I assume if you do this, there is a good chance of it breaking, and or you will find out worn it really is. New there is quite a bit of tension applied, why there should be no bounce to it.
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Got around to putting a new one on but the bounce is still there, although I think it’s a little less?

There definitely is a lot more tension on the new arm and the pulley in the tensioner spins more freely.

What else can I try? New belt?
While you had the tensioner removed did you test spin the Idler Pulley above ?
IF not... You need to check the bearing in the Idler Pulley to ensure it spins freely and smoothly.
I have not observed a tensioner bouncing like that so something is intermittently binding.
When you have the belt off you want to feel every pulley.

If you replaced the tensioner (what brand did you use?) then yes I would probably have replaced the belt and idler pulley.

Also take a good look at your crank pulley. Center is rubber. That's 20 year old rubber...if it's checked or cracked it probably needs replaced.