I recently replaced my belt. The new belt is vibrating excessively. I can hear vibration noise from the belt in the cab at idle. I can see the belt's excess flapping between the alternator and power steering pump. If I hold it down with a screw driver handle the noise stops.

Is it time to replace the belt tensioner? Anyone else experience this problem?

Thanks!

 

Thomas,

It is very possible your tensioner is going bad.

Go outside and take a close look at it. Does it look like this?

 

I second the tensioner.

 

Maybe you have the wrong size belt and a bit too long..just a thought. Check to see if you are towards the end of the travel of the tensioner..

 

He just changed his alternator. His belt was fine before. That sorta tells me that he took the belt off to do his alternator and in the process of taking it off/putting it back on his tensioner took a crap.

 

Dang, Lisa. Was that off of your truck? I bet that wobbled like heck.

 

No, I stole it off another forum..

I did have an idler pulley go out once though. Kept shredding my serp belt.

 

I agree. Could be tensioner or the replacement belt is bigger.

He changed his alternator?

 

Yes, its on another thread of his. He was having some idling issues and learned he had a bad alt. He then changed his alt and noticed his belt was slappin around a bit at idle.

 

Is the pulley the same diameter on the new alt?

 

Good question. How could it not be?

 

I dunno, just throwing it out there. Maybe, just maybe the rebuilt house installed the wrong size pulley??? You might be right with your earlier comment, the fact that the tensioner was on it's last legs and by messin' with it during the alt swap, she broke.

 

I hadn't thought about that. It could also be that he changed out his serp belt and just didn't mention it.

I guess we'll just have to wait for him to get off work...

 

Subscribing for knowledge,not trying to high jack but every time I replace my belt, about two to three weeks later the belt stars to wear and get jagged on one side. Im thinking tensioner or idler pulley,it also whines a little but if I spray the TOP of the belt with WD...it quits whing for a while.

 

Nice job paying attention and tying all the threads together. I guess the question now is was the belt replaced at the same time as the alternator to help narrow down the suspects.

Good question, but the size of the pulley would have to be different significantly in my opinion to make the belt vibrate like that. If you look at the HO alts from DB-electrical, you'll notice they come with an undersized pulley to increase output at low RPM's. The real question is at what point does the tensioner engage the belt? If it's all the way out, or very close, this may be the problem. The same result could come from the belt being too long.

I'd take the belt off and spin all the pulleys by hand. After torquing the injectors and rockers on my wife's truck, I noticed a faint hum from her truck. I pulled the belt and found the idler pulley didn't sound quite right. Replaced that and the problem was solved.

Interesting side note; Orielly's did not show a part number for an idler pulley on our engine even though the belt diagram clearly showed it. The Autozone across the street not only showed the part number, but they had the part in stock.