Puzzeler
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Racer
Joined: Apr 2010
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From: New Prague MN
Puzzeler
Okay, here we go. 1986 L98
There was a bad rattle in the area of the AC whenever the AC was running (original compressor and clutch btw) so I swaped out the compressor, recharged etc. There was still a rattle after all was done. The mechanic who recharged my system for me bet me a beer it was the belt tensioner, so I swapped that out. Sonofabuck owes me a beer. The rattle remains, but only when the AC is on. I suppose it is possible that I have another bad tensioner, but I figured I would check for any input before I go further. Just looking for other possibilities.
Casket
There was a bad rattle in the area of the AC whenever the AC was running (original compressor and clutch btw) so I swaped out the compressor, recharged etc. There was still a rattle after all was done. The mechanic who recharged my system for me bet me a beer it was the belt tensioner, so I swapped that out. Sonofabuck owes me a beer. The rattle remains, but only when the AC is on. I suppose it is possible that I have another bad tensioner, but I figured I would check for any input before I go further. Just looking for other possibilities.
Casket
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Do you still have the frisbee on? Its designed to smooth out belt when AC is on.
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Racer
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From: New Prague MN
I am still a novice, but did the 86 come with a frisbee? I never removed one, and have not seen one either. I purchased this car last fall. This is really the first trouble spot I have had. I just replaced the belt as well, and it is still a little noisy. Guessing it is either this frisbee issue, or a bad from the box tensioner.
Last edited by Casket86; Jul 10, 2010 at 09:39 PM.
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I dont know if the frisbee was on your year model. The frisbee is a nickname for a large circular metal disk that runs on the front of the water pump to minimize belt movement when AC is on
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Racer
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From: New Prague MN
Yep, did the belt too. The rattle is not nearly as bad with the new belt and tensioner and is now only present at idle. The slightes increase in rpms and it goes away as the tensioner becomes more static. At idle the new tensioner tends to want to bounce. I am thinking that my new tensioner may be bad. I did notice some scratches on top of the pulley arm right out of the box. Makes me think that this particular unit has been installed and returned before. I am gonna have them order up a replacement. I need to get this fixed asap as we are heading out to the Black Hills Corvette Classic in Spearfish South Dakota on Wednesday. God I can't wait. And yes, I know......pictures. Lots and lots of pictures. Thanks for the input thus far, and any more that may be forthcoming.
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Racer
Joined: Apr 2010
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From: New Prague MN
Do you recall what brand tensioner you used? I see that O'reilys has Gates ($95.99) or Dorman ($58.99). The one that I put on was a gates (I ordered over the phone, bastards never said anything about a cheaper one).
Last edited by Casket86; Jul 10, 2010 at 11:02 PM.
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I am still a novice, but did the 86 come with a frisbee? I never removed one, and have not seen one either. I purchased this car last fall. This is really the first trouble spot I have had. I just replaced the belt as well, and it is still a little noisy. Guessing it is either this frisbee issue, or a bad from the box tensioner.
'86 didn't have a frisbee.
Racer
Joined: Mar 2010
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From: Temecula Cali
If the tensioner is bouncing around when the car is idling with the AC on, then compare with the AC off.
If the tensioner movement is considerably more violent when the AC is on, see if the car's idle speed is staying within specs. The idle speed itself might be too low.
Rob
If the tensioner movement is considerably more violent when the AC is on, see if the car's idle speed is staying within specs. The idle speed itself might be too low.
Rob
Last edited by chileverde; Jul 11, 2010 at 12:27 AM.
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Racer
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From: New Prague MN
Thanks for all the good input.
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Temporarily adjusted Idle speed to 800. Does not chatter as bad, but still there. O'Reileys will have a replacement for me by 4:30 today. I does not appear to be un-driveable as the belt is running true and in line. The chatter is just annoying as well as a little embarassing.
Thanks for all the good input.
Thanks for all the good input.
Racer
Joined: Mar 2010
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From: Temecula Cali
if the new tensioner doesn't rid you of the vibration...
changing out the alternator pulley to a decoupling style pulley will reduce torque strain on the belt system and should alleviate the tensioner rattle. it acts as a damper of sorts and reduces strain on the belt assembly.
the C5's got this as a fix for the same problem on A4 equipped models with customers complaining of the same issue.
info link: http://www.alternatordecoupler.net/f...itensOAD-2.pdf
the C5 pulley will fit the C4 alternator, and can be found on ebay for around 70 bux. the spline tool to install one is another 20.
rob
changing out the alternator pulley to a decoupling style pulley will reduce torque strain on the belt system and should alleviate the tensioner rattle. it acts as a damper of sorts and reduces strain on the belt assembly.
the C5's got this as a fix for the same problem on A4 equipped models with customers complaining of the same issue.
info link: http://www.alternatordecoupler.net/f...itensOAD-2.pdf
the C5 pulley will fit the C4 alternator, and can be found on ebay for around 70 bux. the spline tool to install one is another 20.
rob
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Racer
Joined: Apr 2010
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From: New Prague MN
Just wanted to say thanks to all for the input.
Oddly enough (and I still can't believe this) the problem was an over filled ac system. The shop that charged my system put in a little too much. I guess the higher pressure works the motor just a little too hard? Anyway, the shop near where I work reduced the charge by a few pounds and the rattle is gone. I would not have believed it if I did not watch the whole process.
Thanks again all. This forum is fantastic when it comes to helping people out.
Oddly enough (and I still can't believe this) the problem was an over filled ac system. The shop that charged my system put in a little too much. I guess the higher pressure works the motor just a little too hard? Anyway, the shop near where I work reduced the charge by a few pounds and the rattle is gone. I would not have believed it if I did not watch the whole process.
Thanks again all. This forum is fantastic when it comes to helping people out.
Last edited by Casket86; Jul 13, 2010 at 05:56 PM.
Racer
Joined: Mar 2010
Posts: 291
Likes: 1
From: Temecula Cali
Just wanted to say thanks to all for the input.
Oddly enough (and I still can't believe this) the problem was an over filled ac system. The shop that charged my system put in a little too much. I guess the higher pressure works the motor just a little too hard? Anyway, the shop near where I work reduced the charge by a few pounds and the rattle is gone. I would not have believed it if I did not watch the whole process.
Thanks again all. This forum is fantastic when it comes to helping people out.
Oddly enough (and I still can't believe this) the problem was an over filled ac system. The shop that charged my system put in a little too much. I guess the higher pressure works the motor just a little too hard? Anyway, the shop near where I work reduced the charge by a few pounds and the rattle is gone. I would not have believed it if I did not watch the whole process.
Thanks again all. This forum is fantastic when it comes to helping people out.
