96 850 Wagon Belt Noise
 

A while back I noticed that during cold-starts with <70F outside, I would get a squealing belt noise on startup. The colder it got, the longer it would take for the noise to start, and the longer it would take for the noise to stop. When the Temp gage reached ~1/3 from bottom, the noise would typically stop. However as soon as I started to drive, the noise would return and vary with Engine RPM. I could not hear it above 2k rpm and/ or 25-30 mph due to engine/road noise.

I had the serpentine belt and tensioner assembly replaced which eliminated the while-driving squealing, but I still get the noise on startup. The belt was very old and the tensioner spring was loosening up and the pulley not moving smoothly, which all seem to be contributing factors.

The Mechanic who did these repairs is new to me as I have just moved, but he reported that all the other pulleys for the belt looked and felt fine.

The noise continues to come from the serpentine belt area, but is hard to pin-point exactly where it is coming from.

Does anyone have any suggestions and or experience with something like this?

Thanks,
-Decaff

Assuming you don't have something like a T-belt pulley or water pump going bad, which could be disasterous, I'd be looking at the alternator.

I have not had any electrical issues indicative of a bad alternator. A couple months before the noise started I left my lights on over night and drained my battery. After getting a jump from AAA, I was able to charge the battery back up with a few hours of driving (65% after one hour). I have not had an electrical issue since.

Are there other signs I should be looking for to indicate a bad alternator? What made you think of the alternator besides it also being on the Serpentine belt?

Thank you for your response,
-Decaff

idlers could be going. You'd have to pull off the belt and feel by hand.

Sounds like a bad bearing in the alternator. If you can hear the squeak at idle, turn your lights on heater on etc see if the pitch changes, not fool proof method but may help point you in the right direction.

Take the serpentine belt off and start the car.....if it is quiet, you know it is associated with the serpentine belt system, ( if not, you probably have an issue with the timing belt system). Next, put the belt back on, start the car and once it starts squealing, spray the belt with some belt dressing (you can buy a spray can of it at most auto parts stores). If it stops suealing, you have a slipping belt. If it still squeals, it is most likely a belt pulley or idler. Start small and change the pulleys and idlers. my last suggestion would be the alternator.

Get some fuel size hose about 2 feet long. Hold one end to your ear and the other move it around the area to pin point what is squeaking. Then replace it

great idea! I have to do this for my daughter's 850T and happen to have some old fuel hose (really!)

It's amazing how well that works. I use vacuum hose so it can fit inside my ear. Even better.