how tight should the serpentine belt be?
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Member
Joined: Jul 2008
Posts: 222
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From: Daytona Beach, Fl
Year: 1988
Model: Cherokee
Engine: 4.0
i ended up having to replace the idler pulley on mine today.. from what ive heard its a common problem with these.. someone told me it should be loose enough to be able to spin the idler by hand with the belt in place... is this true.. im in water a good bit so i dont want any squeling.. thankss
Isnt it kind of hard to say a definite measurement? I mean I may push harder than you, or you than me, and that would give me more or less but in fact the belt is the same tightness. If that makes any sense.
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Joined: Mar 2010
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From: Gilbert AZ/Las Cruces NM
Year: 1996
Model: Cherokee
Engine: 4.0 upgraded
if you are squealing from the bearings it is TO tight lol. but yes about 1/2" of wiggle. and no matter how hard you push or pull the belt will only stretch so much lol so 1/2" is pretty accurate.
btw. that is 1/2" at your longest span from pully to pully
btw. that is 1/2" at your longest span from pully to pully
Honorary Moderator
Joined: Mar 2010
Posts: 8,135
Likes: 16
From: Gilbert AZ/Las Cruces NM
Year: 1996
Model: Cherokee
Engine: 4.0 upgraded
where did you read that? i just checked my FSM (i have a few different years) and all it says is:
Using serpentine belt tension gauge, tighten adjusting bolt until belt reaches proper tension. Refer to Belt Tension at the rear of this section for proper belt tension.
125 foot pounds is a TON of torque.... Like body weight when tightening lug nuts.... TO MUCH TORQUE for a belt.... I can tell you that!
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Joined: Aug 2010
Posts: 127
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From: Des Moines, IA
Year: 2001
Model: Cherokee
Engine: 4.0
Well, I don't know where I read it, but you can't compare it to lugs because you've got a leverage thing going on here. I can't swear that's what I read but it sure rings a bell for my 01. Also, look through these Fora and yo'll see a lot of broken adjusters.
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Joined: May 2010
Posts: 57
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From: SW Oklahoma
Year: 1988
Model: Cherokee
Engine: 4.0
I think being able to turn the idler by hand might be a little bit too loose. I've always adjusted mine to about 1/2" deflection. But adjust it to whatever you want... it's yours. If it works it works... and if it don't it don't. And if it don't it won't be long before you find out it didn't then you'll rethink it and maybe do it a little different the next time. Maybe a little tighter... maybe a little looser... and it'll still be yours til you trash it or sell it.
CF Veteran
Joined: Apr 2008
Posts: 7,661
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From: Smiths Station, Al
Year: 87
Model: Wagoneer
Engine: 4.0 I6
I do the twist that is what I learned when I was a kid and it has always worked.
Twist your belt if you can twist it more than 90 deg it is loose. If you can't twist it 90 deg then it is too tight. RIght at 90 degrees is good to go.
Twist your belt if you can twist it more than 90 deg it is loose. If you can't twist it 90 deg then it is too tight. RIght at 90 degrees is good to go.
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Joined: Dec 2009
Posts: 231
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From: Lincoln, Nebraska
Year: 2000
Model: Cherokee
Engine: 4.0
between what two accessories are you twisting?


