yzinger

Hi folks, i know i know...use the search function. But, i thought maybe having a new post would be ok and maybe help others.

2007 150 - 5.4l

How are you guys determining that you have a bad belt as opposed to bad bearings or the like?

In my case it is very apparent when wet out. Seems to be not as bad when dry out. Of course it is a little worse when under load. Doesn't matter engine hot or cold. Doesn't matter heat on or off. Doesn't get louder when turning.

I tend to think belt but I really cant be sure and dont want to start just replacing pulleys etc..

R&TBabich

When you take the belt off and spin the pulleys you can usually easily feel how smooth the bearing spins or not.
With the belt off if it looks fine it probably is.
An idler/tensioner pulley bearing is usually the first to go before the belt or any accessory bearing.
If you have a vise the bearings can be replaced in the pulleys.

yzinger

Thanks for note and here is an update. In my case it was the belt...although, visually it looked "ok".

What I did was with engine running simply have a good look making sure belt was running true on each pulley, this isn't that accurate but with fairly bad bearings you would see some movement in the pulley. Once that was ok I dripped drops of water on the ribbed side of the belt (anywhere you can reach) and right away the noise ceased. Although this tests do not rule out the tension arm I felt comfortable that I had a belt issue. As I said, the belt looked good as far as cracking, chips out etc but it was stretched a fair amount.

Hope this helps someone down the road and thanks for looking folks.