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Rattling Noise In Front Of Motor

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Red Regal T

Senior Member
Joined
May 24, 2001
Messages
19,243
Developed a rattling noise in the front of my 3800 motor. It's more pronounced at idle and when you rev it, it seems to go away, but continues at idle. Checked pulleys, AC compresser, alternator and the noise isn't coming from them. I started it with the belt off and the noise went away, too. I think it has something to do with the timing chain. I'd like to get some opinions before I even start to go in there. The car is an 88 Toro with 112,000 miles. TIA
 
I would think that if the noise went away with the belt off it couldn't be the timing chain. At that point the timing chain would still be moving, just not all the front accessories.

Adam
 
Since you said you remove the belts and the noise when away. it leaves me to believe you might have a bad bearing on one of the pulleys. sometime the tensioner and idler pulley will make this noise (if plastic). what you should do is remove all belt (with engine off :D ). now spin each pulley one at a time. listen for noises coming from the bearing. also you might want to look into the alternator pulley.
 
Forgot to post back that I found the problem. The problem was the harmonic balancer. I had to replace it. The rubber in the balancer cracked pretty much all the way around. You could move the outer ring about 1/3 of the way around before it would stop. When it moved to it's limit, it caused the knocking noise.
 
Originally posted by Red Regal T
Forgot to post back that I found the problem. The problem was the harmonic balancer. I had to replace it. The rubber in the balancer cracked pretty much all the way around. You could move the outer ring about 1/3 of the way around before it would stop. When it moved to it's limit, it caused the knocking noise.
i had 2 balancers go bad just like that!!
 
watch those damn plastic idler and tensioner pulleys
i had one fly off and destroy the SC belt
it too made a rattling sound before it came off its bearing
 
I had the exact same problem a couple of months ago, it took me a while to locate the rattle, and after replacing my powersteering pump, I noticed the shredded Harmonic ballancer. $185.@Genuine Auto"
 
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