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Sam
09-05-2001, 09:58 AM
Hello all,<p><br>Sometime when I accelerate with the AC on I noticed a loud squeal from under the hood. If I turn the AC off the squeal will stop. I looked at the three belts and they look ok. What else could be the problem or why do normal looking belt make this noise? Thanks in advance. Everyone is always so helpful.<p>Sam<br>1992 735il 88750

Mark Petry
09-05-2001, 10:45 AM
Sounds like a slipping belt, Sam. Look for glazing one the belt (visual inspection is pretty hard on an E32) or use some "belt grab". You can tighten them too but don't over do it, as you'll cause premature wear on the bearings in the accessories.<p>markp<br>90 750iL<br>Banibridge Island, WA<br><i><br>Hello all,<p><br>Sometime when I accelerate with the AC on I noticed a loud squeal from under the hood. If I turn the AC off the squeal will stop. I looked at the three belts and they look ok. What else could be the problem or why do normal looking belt make this noise? Thanks in advance. Everyone is always so helpful.<p>Sam<br>1992 735il 88750<p></i><br>

Wayne McKay
09-05-2001, 12:06 PM
You didn't mention which, 735 or 750, and I don't have the Bentley here this morning to see if it matters; but on the 750 there are actually two belts. Both are held at the correct tension with a tensioner pulley/bracket assembly and a tensioner piston. As in previous post, the belt itself can become stretched, worn, glazed, etc. - an easy situation to deal with.<br>The more serious issues revolve around the tensioner system itself:<br>1. tensioner piston weakened - an easy situation to deal with (bought one for $37 USD about three weeks ago)<br>2. tensioner pulley broken - not likely as the reduced diameter results in not enough tension to run the belt at all (bought one for $51 USD about three weeks ago)<br>3. <b>URGENT</b> tensioner assembly mounting bolt - on casual visual look around, found one of the tensioner bolts had worked loose leaving the assembly to wander about " in/out from the block. Due to the ribbing on the belt it tended to stay put and was wearing against the tensioner assembly - assembly was weakened and the side of the belt was frayed. Had this continued much longer, I can only assume that the bolt would have worked completely loose and the assembly/belt would have ended up in the fan and likely the radiator as well. This was the case for another poster here a while back. I have photos of this in the 7 series gallery on this site if it will help to know what to look for (link provided).<p>'88 750iL<p><i><br>Hello all,<p><br>Sometime when I accelerate with the AC on I noticed a loud squeal from under the hood. If I turn the AC off the squeal will stop. I looked at the three belts and they look ok. What else could be the problem or why do normal looking belt make this noise? Thanks in advance. Everyone is always so helpful.<p>Sam<br>1992 735il 88750<p></i><br>

Sam
09-05-2001, 12:59 PM
Thanks for the advice. I have looked at your pictures and I will do an inspection this afternoon.<p><p>You didn't mention which, 735 or 750, and I don't have the Bentley here this morning to see if it matters; but on the 750 there are actually two belts. Both are held at the correct tension with a tensioner pulley/bracket assembly and a tensioner piston. As in previous post, the belt itself can become stretched, worn, glazed, etc. - an easy situation to deal with.<br>The more serious issues revolve around the tensioner system itself:<br>1. tensioner piston weakened - an easy situation to deal with (bought one for $37 USD about three weeks ago)<br>2. tensioner pulley broken - not likely as the reduced diameter results in not enough tension to run the belt at all (bought one for $51 USD about three weeks ago)<br>3. <b>URGENT</b> tensioner assembly mounting bolt - on casual visual look around, found one of the tensioner bolts had worked loose leaving the assembly to wander about " in/out from the block. Due to the ribbing on the belt it tended to stay put and was wearing against the tensioner assembly - assembly was weakened and the side of the belt was frayed. Had this continued much longer, I can only assume that the bolt would have worked completely loose and the assembly/belt would have ended up in the fan and likely the radiator as well. This was the case for another poster here a while back. I have photos of this in the 7 series gallery on this site if it will help to know what to look for (link provided).<p>'88 750iL<p><br>Hello all,<p><br>Sometime when I accelerate with the AC on I noticed a loud squeal from under the hood. If I turn the AC off the squeal will stop. I looked at the three belts and they look ok. What else could be the problem or why do normal looking belt make this noise? Thanks in advance. Everyone is always so helpful.<p>Sam<br>1992 735il 88750<p><br></i><br>


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