Belt noise only at idle. This one is tricky.

So, here is the deal.
I replaced my water pump, pulleys (idler, tensioner, and water pump), and belts. Things were working perfectly for about a year. Then, one night me and my best friend did two 0-60 runs just to see how fast my 97 528 was. This was the only abnormal driving I did since I baby the car. Anyway, about 3 days after that I noticed a small squeaking sound only at idle, the second I hit the gas, it went away completely. Now, I thought that it must be the tensioner which is mechanical and I've been lurking on the forums enough to know that these go bad. So I did a water test I saw on youtube and sprayed water directly onto the belts. When lubricated the squeak goes away for about 15 seconds and comes back. As I understand things, when the tensioner is bad lubrication with water increases the squeaking as the belt slips more. So, doing more research I am seeing that this may be a belt alignment issue? If anyone has any experience with this problem I would love to hear your thoughts.

dont push old pony !!!

Mine only squeaks when i first start it but i know my tensioner is bad. My car has the hydraulic tensioner and i can watch it colapse when try to turn the fan clutch nut.

Release the tension on the belt and spin the tensioner pulley by hand. If it spins freely the grease is gone and it needs to be replaced. It should not rotate more than one revolution if the grease is still packed in it's bearing.

You can try to re-pack the bearing by gently prying out the seal but it didn't last very long when I tried doing it.

Originally Posted by Tuskfish

Release the tension on the belt and spin the tensioner pulley by hand. If it spins freely the grease is gone and it needs to be replaced. It should not rotate more than one revolution if the grease is still packed in it's bearing.

You can try to re-pack the bearing by gently prying out the seal but it didn't last very long when I tried doing it.

You were using the wrong grease. Get some Timken High Speed Spindle grease, it's much thicker than regular wheel bearing grease. Those idler pulleys spin ~2x faster than the engine.

I used MAG1 Hi-temp Disc Brake Wheel Bearing Grease 30k ago to repack the idler bearings. I just recently replaced the belts, and repacked the idler bearings. The grease was still in pretty good shape.

I repacked mine with walmart synthetic and it has been holding up for 2 years...I am not sure this is the idlers, I am thinking more of a waterpump issue, hopefully you got one with a limited lifetime warranty ...

I bought four new idlers from pelican for $23 each 2 months ago. Going in this weekend with both belts and the main tensioner. Pretty much the whole system except for the a/c tensioner.