[JordanS]

My 04 Intrepid SE with the 2.7 has a strange issue. My crank pulley is wobbling and I can move it under the tension of tight belts. It only seems to do this at idle though. Sometimes it’s wobbling a lot, sometimes it’s not wobbling very much. Sometimes it makes noise at idle, sometime it doesn’t. I haven’t really been able to find a solution yet and everyone I’ve talked to has told me just to keep using it and monitor it. I’m concerned that it will get so wobbly that it throws the belt and I’ll be stranded on the side of the road. Does anyone have any idea I about what this might be?

 

[peva]

So it is constructed of (1) a hub, (2) the outer ring (whose ID is larger than the hub's OD) with the belt grooves, and (3) a thick band of rubber that is interference fit between the hub OD and outer ring ID.

The rubber band allows some vibration of the outer hub (varies with engine speed) to counter/negate natural resonances of the engine. That's why it is called a damper pulley, or harmonic balancer. But the movement/vibration is by slight distortion of the rubber band - not by slipping of the hub or band.

You might see it normally vibrate (wobble) a little more than 1/16" at some speeds, but probably not as much as 1/8".

But if you're saying that you can easily move (not by distorting the rubber, but by slipping) the outer ring relative to the hub by hand, the rubber has degraded and is probably shrinking and cracking - you need to replace the pulley. Imagine the damage it can do if the ring comes off the hub and belts, spinning at 3 to 5 thousand rpm, plus, until that happens, it's slipping from torque needed to spin the a.c. compressor, p.s. pump, and alternator when they're needed most.

 

[kinkis_23]

I just replaced the crank pulley on my 97 3.5 this week because it also wobble on idle and the belt chirped a bit, pretty easy job with the right tools, I borrowed the chrysler pulley extractor from Autozone.

That should take care of your problems, the pulley is cheap also.

 

[JordanS]

So it is constructed of (1) a hub, (2) the outer ring (whose ID is larger than the hub's OD) with the belt grooves, and (3) a thick band of rubber that is interference fit between the hub OD and outer ring ID.

The rubber band allows some vibration of the outer hub (varies with engine speed) to counter/negate natural resonances of the engine. That's why it is called a damper pulley, or harmonic balancer. But the movement/vibration is by slight distortion of the rubber band - not by slipping of the hub or band.

You might see it normally vibrate (wobble) a little more than 1/16" at some speeds, but probably not as much as 1/8".

But if you're saying that you can easily move (not by distorting the rubber, but by slipping) the outer ring relative to the hub by hand, the rubber has degraded and is probably shrinking and cracking - you need to replace the pulley. Imagine the damage it can do if the ring comes off the hub and belts, spinning at 3 to 5 thousand rpm, plus, until that happens, it's slipping from torque needed to spin the a.c. compressor, p.s. pump, and alternator when they're needed most.

Ok that doesn’t sound like a terrible job. But you’re saying it would be unsafe to drive atm?

 

[peva]

Ok that doesn’t sound like a terrible job. But you’re saying it would be unsafe to drive atm?

Chances of something happening are slim, but possible. I wouldn't just let it go forever. If it is slipping from the belt loads (which if you're able to slip it by hand, it likely is) that rubber band is going to wear and get looser and looser. I wouldn't want the outer metal ring coming off of the hub spinning at a few thousand rpm. An ounce of prevention . . .

 

[JordanS]

Chances of something happening are slim, but possible. I wouldn't just let it go forever. If it is slipping from the belt loads (which if you're able to slip it by hand, it likely is) that rubber band is going to wear and get looser and looser. I wouldn't want the outer metal ring coming off of the hub spinning at a few thousand rpm. An ounce of prevention . . .

Ok. I already ordered the new harmonic balancer and it will be here soon. Until I can get it installed, I’ve been periodically tightening the belt whenever I notice the pulley is moving an excessive amount (enough to make noticeable knocking noises).

 

[peva]

Ok. I already ordered the new harmonic balancer and it will be here soon. Until I can get it installed, I’ve been periodically tightening the belt whenever I notice the pulley is moving an excessive amount (enough to make noticeable knocking noises).

Tightening the belts isn't going to help anything. The slipping I mentioned is between the pulley's rubber band and hub and outer ring - not between the serpentine belts and the pulley. If the pulley is making knocking noises, it's pretty loose. I'd drive it as little as possible until you replace the pulley.

 

[JordanS]

Tightening the belts isn't going to help anything. The slipping I mentioned is between the pulley's rubber band and hub and outer ring - not between the serpentine belts and the pulley. If the pulley is making knocking noises, it's pretty loose. I'd drive it as little as possible until you replace the pulley.

Ok. It did seem to help some when I tightened my tensioner but yea. I try to keep the revs as low as possible to reduce wear on the balancer until I can get it replaced.