Car keeps throwing off the belt?
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From: South Carolina
Car keeps throwing off the belt? Hey guys,
Forewarned I did a search, but all the results were archived and not useful. So onto the problem at hand. My car keeps throwing the serpentine belt off? First time i was running it pretty hard, but the second it just popped off while idling? I saw somewhere about making sure the power steering pulley was correct or something? Any input would be appreciated.
Forewarned I did a search, but all the results were archived and not useful. So onto the problem at hand. My car keeps throwing the serpentine belt off? First time i was running it pretty hard, but the second it just popped off while idling? I saw somewhere about making sure the power steering pulley was correct or something? Any input would be appreciated.
Yes...in short.....because this has been talked about to death. And yes, I know the search does suck sometimes.
The factory belt tensioner is a garbage design....all GM had to do was make a FIXED tensioner....((it would have been cheaper for them to do this)). They dropped the ball and designed this spring loaded thing. It does three things....1) it causes the belt to stretch which makes it come off easier. 2) It bounces when you really wack the throttle. 3) The tensioner spring loses its strength over time and it loses its tension.
Wacking the throttle on a stock engine really doesn't matter and it shouldn't come off....but that bouncing along with belt stretch, it will start to throw the belt off. OR...a built/modded engine will start to throw belts with the factory tensioner.
This started happening to me the instant my 427ci was installed.........
Get a Katech "fixed" tensioner and your problems are 100% solved. You will also have a belt for 9 or 10 years without any stretching. My belt is almost 10 years old and looks new....AND the tensioner is in the same exact place it was 10 years ago and the belt is still tight, proving the fixed tensioner eliminates belt stretch......
Buying a new factory tensioner would be a terrible thing to do....get the Katech and you'll be good for any increase in HP you do to the engine down the road.
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The factory belt tensioner is a garbage design....all GM had to do was make a FIXED tensioner....((it would have been cheaper for them to do this)). They dropped the ball and designed this spring loaded thing. It does three things....1) it causes the belt to stretch which makes it come off easier. 2) It bounces when you really wack the throttle. 3) The tensioner spring loses its strength over time and it loses its tension.
Wacking the throttle on a stock engine really doesn't matter and it shouldn't come off....but that bouncing along with belt stretch, it will start to throw the belt off. OR...a built/modded engine will start to throw belts with the factory tensioner.
This started happening to me the instant my 427ci was installed.........
Get a Katech "fixed" tensioner and your problems are 100% solved. You will also have a belt for 9 or 10 years without any stretching. My belt is almost 10 years old and looks new....AND the tensioner is in the same exact place it was 10 years ago and the belt is still tight, proving the fixed tensioner eliminates belt stretch......
Buying a new factory tensioner would be a terrible thing to do....get the Katech and you'll be good for any increase in HP you do to the engine down the road.
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Last edited by LS6427; Dec 28, 2011 at 06:48 PM.
Get this one for $100........its only like $30-$40 more than another junk factory one. You will save in the first 3-4 years because you won't need a new belt in 10 years. Its paid for after that.
http://www.ebay.com/itm/LS1-LS2-LSX-...f#ht_500wt_949
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http://www.ebay.com/itm/LS1-LS2-LSX-...f#ht_500wt_949
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Before you go jumping for parts... make sure that your current tensioner is faulty! There are 10 different things that can cause this to happen. Your tensioner may be fine. First, start with the easy stuff:
- Look at the belt routing diagram on the driver's side shock tower. Does your routing match it?
- The tensoner has index marks on it. What does yours look like when the belt is on? The one mark on the pulley side should be between the two marks on the tensioner body.
- When was the last time you changed your belt? How old is it? Are all the grooves on the inside of the belt still good?
- How does your PS pulley, Alternator pulley, and crank pulley look? Are all the grooves still in good condition on them?
- Is your car stock? Any changes to the engine accessories?
- Look at the belt routing diagram on the driver's side shock tower. Does your routing match it?
- The tensoner has index marks on it. What does yours look like when the belt is on? The one mark on the pulley side should be between the two marks on the tensioner body.
- When was the last time you changed your belt? How old is it? Are all the grooves on the inside of the belt still good?
- How does your PS pulley, Alternator pulley, and crank pulley look? Are all the grooves still in good condition on them?
- Is your car stock? Any changes to the engine accessories?
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Joined: Aug 2006
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From: Knappa, Oregon
I bent a tensioner once by applying too much pull on the wrench when I changed the belt. It was pretty easy. After that it kept throwing the belt.
I took a close look at it and damn, the tensioner had a little tilt to it. And I did not use a great deal of force. Had to replace the tensioner and the problem went away.
Now I am real gentle and only use enough force to release the belt.
I took a close look at it and damn, the tensioner had a little tilt to it. And I did not use a great deal of force. Had to replace the tensioner and the problem went away.
Now I am real gentle and only use enough force to release the belt.
Gatorbacks are better but that isnt why the car is throwing belts. If the tensioner is bouncing around or the pulley is misaligned then it will literally force the belt off the accessories.
Personally op I think its the tensioner my stock one thre the belt once at high rpm then was ok as long as I wasnt beating on it eventually it got to the point it was throwing it off at idle. New katech tensioner and its all good now
Care to share why a new tensioner is a better fix? New pully solves the problem just as well and costs more than $100 less.
The stock tensioner will tell the tale, though. The tensioner has a spring in it. Springs go bad. When the tensioner spring goes bad, you can tell it by the tension marks on the unit. If the tensioner is good and the car is throwing belts during normal driving - there is a problem elsewhere. Forcing the belt to stay on when there is a non-tensioning problem will just chew up the belt.
IMO - For a daily driver, I'd rather have the stock tensioner design if I loose a belt and have to fix it by the side of the road. The old school manual tensioner make more sense when racing.
... Because the OP already bought a manual tensioner. In the end, a larger pulley might help a weak tensioner, but it won't cure one.
The stock tensioner will tell the tale, though. The tensioner has a spring in it. Springs go bad. When the tensioner spring goes bad, you can tell it by the tension marks on the unit. If the tensioner is good and the car is throwing belts during normal driving - there is a problem elsewhere. Forcing the belt to stay on when there is a non-tensioning problem will just chew up the belt.
IMO - For a daily driver, I'd rather have the stock tensioner design if I loose a belt and have to fix it by the side of the road. The old school manual tensioner make more sense when racing.
The stock tensioner will tell the tale, though. The tensioner has a spring in it. Springs go bad. When the tensioner spring goes bad, you can tell it by the tension marks on the unit. If the tensioner is good and the car is throwing belts during normal driving - there is a problem elsewhere. Forcing the belt to stay on when there is a non-tensioning problem will just chew up the belt.
IMO - For a daily driver, I'd rather have the stock tensioner design if I loose a belt and have to fix it by the side of the road. The old school manual tensioner make more sense when racing.
Wssix curious as to wy you wold prefer the spring tensioner for a daily driver I've taken the belt of my katech a couple times and i dont really find it anymore difficult it just requires a 3/8 wratchet and a 15mm wrench.
In a jam on the side of the road, you can press the stock tensioner arm down with a screwdriver, stick, stiff roadkill, etc. to allow the belt to slip on. Otherwise, one would need the wrenches handy. (Personally, I carry wrenches and ratchets in my car - along with a spare belt. Although I expect most people don't.)
