Replacing the serpentine belt and am trying to determine how tight to tighten it.


I can tighten it until it is not slipping but then wonder if it did slip some and damage it or over tighten and end up damaging one or more pulley's


What do you guys do?

 

I just tighten it until it stops squealing. Make sure to have the AC on so it will have the extra load on it. You may have to re-tighten it in a week or so once it breaks in and stretches. They do have to be stupid tight. Some like to use a belt tension gauge.

 

Find the longest section of belt, (left side of water pump) tighten until you have 1/8" flex.

 

Go to any autoparts store buy a $2 belt tension gauge. Tight belt to approx 150lbs of tension.

 

It only takes 30-45 seconds to loosen the idler pulley, turn the adjusting bolt 1/2 turn and re-tighten the idler pulley. After we installed a new belt, it took us 6-7 ever so slight increases in belt tension to get to the "no squeak/squeal" point when the a/c compressor engaged.

Taking a little extra time to snug the belt in ever so slight increments assures the least amount of tension/load on pulley bearings/bushings AND a quiet belt.

 

+1 best way to install a new belt is to just tighten it until it stops squeaking. New belts will ALWAYS stretch over the first month or so so you WILL need to tighten it again. Like djb383 said, tighten it until you get no noise, no more. Best of both worlds.

If you don't know quite how to actually pull the tightening off:

 

Good advice from the previous posters. It's amazing (even after 4 of these things) how tight the belt has to be to work properly.

 

Check the longest section of belt, proper adjustment of the belt gives you about 1/8" deflection.

 

^^^

All belts are not created equal!
So this is the best method!

 

Oh yes, for the best chance of success, Goodyear Gatorback belts can't be beat!

 

I always have issues re-tightening my belt when I take it off (so much, that I am afraid of taking the belt off).

The best way for me is to get the belt close to what I think it should be, starting on the loose end, starting the engine and tightening it as the motor is running. Basically - keep cranking on it until it stops squealing. Turn the AC on and make sure it does not squeal under load.

New belts need to be re-tensioned after 30 minutes of running as well. And as previously stated - Gatorback belts are freaking awesome, but my roommate has been running a Dayco Poly-V for 8 months with zero issues as well.

 

.....but if a 1/4" deflection still allowed for a silent belt, wouldn't a 1/4" deflection be "easier" on bushings/bearings?......or maybe even 3/8" deflection? My point is, the "near perfect" belt tension is achieved by making very small changes/increments in the belt tightening process 'til the belt no longer squeals.

I said 1/2 turn increments in my original post.......1/4 turn increments would be even better but may take a couple minutes longer to find the "sweet spot" of belt tension. The condition of the belt AND pulleys go a long ways in determining the no-squeal "sweet spot" belt tension.

 

Thanks for all the advise and suggestions.


I got it changed, installed a Dayco belt, that was all Advantage Auto had.


There is a little more to this story. I had been having problems with the AC squealing the past couple of weeks, in the afternoon after setting for 9 hours, cold engine. I would start press on the gas and get a squeal, two minutes later all was quiet.


Moving on, I left work Friday evening, got the squeal and then drove away only to feel the loss of power steering 5 minutes later and the light in my head told me that I lost the belt so I pulled into a parking lot.


I found the belt had come off but also that my top radiator hose had a small hold in it right next to the clamp.


So now I have a new belt, new upper hose with plans to change the lower hose and heater hoses, and do a radiator flush at the same time. Are there any other hoses or other things to do at this time?


Now I am wondering, is it possible I had a pin hole in my hose that was allowing antifreeze to get on my AC pulley and caused the squeaking and this entire Problem?


Check Engine Light. Now my CEL is on, how do I reset it?

 

Yup.

 

Exactly. You want the least amount of tension that does the job right. More tension = more side load on pulleys = shorter bearing life.

Don't just crank on it!