How to isolate idler pulley or alternator pulley squeal?

alkon · Jun 20th, 2005, 02:13 PM

I am trying to isolate an intermittent squeal from my engine area that I hear at startup and then goes away. I recently changed out my water pump so I know it is not that. I have tightened by belts so I know its not that. So, I figure it has to be the alternator or the idler pulley. Though I have tried putting my ear as close to both units as I can (without losing it), I cannot isolate which of the two it is coming from. I was thinking of just changing out my idler pulley, but I found out that it costs about $80 (ouch!). Therefore, I want to know which is the problem unit before I spend my hard earned money. Any suggestions?

DraftEm98 · Jun 20th, 2005, 04:21 PM

Either you overtightened one of your pulleys, or didnt tighten it enough, IMO (in my opinion). Check all of the mounting bolts on both pulleys just see if there is any free play. Using carb spray can work, too, when it comes to cleaning grease, grime, oil and coolant off of belts. Worked for me. Use it sparingly, though, as you dont want carb spray sitting on the belts for too long. Also check the belts for any cracks. It might be a new belt, but not everything will be perfect off the manufacturing line. I used to work at an Advance Auto and we'd get 1 week old belt returns every few weeks or so. Good luck.

IanH · Jun 20th, 2005, 04:36 PM

Quote:

Originally Posted by DraftEm98

Either you overtightened one of your pulleys, or didnt tighten it enough, IMO (in my opinion). Check all of the mounting bolts on both pulleys just see if there is any free play. Using carb spray can work, too, when it comes to cleaning grease, grime, oil and coolant off of belts. Worked for me. Use it sparingly, though, as you dont want carb spray sitting on the belts for too long. Also check the belts for any cracks. It might be a new belt, but not everything will be perfect off the manufacturing line. I used to work at an Advance Auto and we'd get 1 week old belt returns every few weeks or so. Good luck.

I had an interesting squeaking on my 2003 Pathy, my wife complained regularly and we took it in several times. Eventually the service writer heard the noise and we left overnight, as it was at start up the same as the problem here.
Anyway they call and said it’s the belt. Since we were at 35,000 and nearly out of warrantee I was skeptical to say the least.
So I arrived the next morning, the car was squeaking away and a small squirt of Wd-40 on the belt ONLY fixed the noise. It has not come back either.
So my conclusion is the belt is rubbing the side of one of the pulleys. Maybe a pulley is slightly out of true or belt slightly oversize………
Hope this helps........