Squealer
Tech Contributor
Joined: Dec 2003
Posts: 19,384
Likes: 87
From: Horncastle Lincolnshire, England
2023 C5 of the Year Finalist - Unmodified
ET who was one of the C5 design engineers posted a great summary of the system and I’ve copied it below. Run through that procedure to identify where the problem lies. If it’s a belt that’s good news and is fairly straight forward once you work out the technique.
Let the engine cool down first or it gets painful. Identify the main belt tensioner from the picture. It’s the top pulley on passenger side. Place a socket wrench on the tensioner nut and push it toward the middle of the engine until there is enough slack to remove the belt. Repeat this procedure for the A/C belt, although the tensioner is a little harder to reach because it is under the power steering fluid reservoir.
Once you have them off its worth cleaning the pulley with a wire brush.
Putting them back is the reverse process but make sure you install the A/C belt before the main belt.
Here’s a pic to identify the components.
Belt Squeal Courtesy E-T
You have two belt systems on your car. One is the drive belt system, the other is the air conditioner belt system. The drive belt system consists of the serpentine belt, the power steering pump, alternator/gen, water pump, harmonic balancer, idler pulley, belt auto-tensioner pulley. The AC belt system consists of the compressor, harmonic balancer, idler pulley, belt auto-tensioner pulley.
First thing you need to do is isolate which system is squeaking. This can be done by releasing tension on the drive belt tensioner and removing the serpentine belt. This is the outboard belt of the two belt systems. If the squeak goes away, then it’s the belt or a component of the drive system.
If the squeak is still there, then it’s a component of the ac belt system.
To verify this, release the belt tension from the tensioner and remove the belt. If the squeak goes away, then it’s a component of the ac belt system.
A common problem is the belt tensioner on either system but verifying which system is at fault is the proper procedure.
You could replace both belts, but you may still have the squeak. If you want to find the culprit, isolate the system, then spray the belt of the offending system and see if the squeak goes away. Try to stay away from the idler and tensioner while spraying. I find that belt dressing may be good to identify a belt problem, but it is a temporary fix at best.
The real problem has been the tensioner and the idler. Both of these components have a sealed bearing which has been know to dry up or redirect the grease away from the bearing, thus causing the squeak.
If you find that a belt change does not correct the problem, then a change of both the idler and tensioner pulley is in order. If you just change the idler or the tensioner alone, it will cause the other component to go bad in a month or so. This has been the case with many members. There was a change made to the dusts seals to help correct this problem in newer C5's. Lots of tensioner and idler pulleys have been identified as a problem and it can affect either system. One is not more prevalent than the other. So find out which system is squeaking first, in the drive belt system. It could also be the bearing of the alternator, power steering pump, or water pump too, but these are less probable.
Let the engine cool down first or it gets painful. Identify the main belt tensioner from the picture. It’s the top pulley on passenger side. Place a socket wrench on the tensioner nut and push it toward the middle of the engine until there is enough slack to remove the belt. Repeat this procedure for the A/C belt, although the tensioner is a little harder to reach because it is under the power steering fluid reservoir.
Once you have them off its worth cleaning the pulley with a wire brush.
Putting them back is the reverse process but make sure you install the A/C belt before the main belt.
Here’s a pic to identify the components.
Belt Squeal Courtesy E-T
You have two belt systems on your car. One is the drive belt system, the other is the air conditioner belt system. The drive belt system consists of the serpentine belt, the power steering pump, alternator/gen, water pump, harmonic balancer, idler pulley, belt auto-tensioner pulley. The AC belt system consists of the compressor, harmonic balancer, idler pulley, belt auto-tensioner pulley.
First thing you need to do is isolate which system is squeaking. This can be done by releasing tension on the drive belt tensioner and removing the serpentine belt. This is the outboard belt of the two belt systems. If the squeak goes away, then it’s the belt or a component of the drive system.
If the squeak is still there, then it’s a component of the ac belt system.
To verify this, release the belt tension from the tensioner and remove the belt. If the squeak goes away, then it’s a component of the ac belt system.
A common problem is the belt tensioner on either system but verifying which system is at fault is the proper procedure.
You could replace both belts, but you may still have the squeak. If you want to find the culprit, isolate the system, then spray the belt of the offending system and see if the squeak goes away. Try to stay away from the idler and tensioner while spraying. I find that belt dressing may be good to identify a belt problem, but it is a temporary fix at best.
The real problem has been the tensioner and the idler. Both of these components have a sealed bearing which has been know to dry up or redirect the grease away from the bearing, thus causing the squeak.
If you find that a belt change does not correct the problem, then a change of both the idler and tensioner pulley is in order. If you just change the idler or the tensioner alone, it will cause the other component to go bad in a month or so. This has been the case with many members. There was a change made to the dusts seals to help correct this problem in newer C5's. Lots of tensioner and idler pulleys have been identified as a problem and it can affect either system. One is not more prevalent than the other. So find out which system is squeaking first, in the drive belt system. It could also be the bearing of the alternator, power steering pump, or water pump too, but these are less probable.
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