200sportxj

So I put a new belt on my jeep a week ago to fix a squeeling issue i had.

it would randomly squeel and when it did my volt-o-meter would drop to nothing, then after slipping for a little while it will shoot right back up and stop squeeling.

so first thing i thought was a bad pulley or alternator.

so i pulled it all apart and the alternator appears to be find and no pulleys have bad bearings.

BELT IS BRAND NEW, AND TIGHT AS CAN BE.

Is it possible that the alternator is on its way out and its starting to lock up and then breaks free? it just started 2 weeks ago....

I have it all apart and at 5 o clock my time imma be leaving my house to go to o reillys and get a alternator unless someone tells me otherwise.

RTorrez1

If you are sure that all your pulleys and bearings including the alt. are fine you may need to tighten your belt. I do know that after putting a new belt they need to be re-tightened because they do stretch after about a wee or two.

200sportxj

It did it the same day, and its as snug as it can get.

I pryed the pulley up with a pry bar and had the bolt all the way lossened, then tightened the pulley and then threaded the bolt all the way tight so there is no more room to tighten...

RTorrez1

Do you think that maybe you over tightened it the first time and over stretched the belt. It can happen, I did it before. Hope not but it is possible. You should have a lot of adjustment. That's why I'm thinking this

tgordon

Belt too tight can cause problems. Grab the belt between thumb and index finger then twist it. If you can twist it about 45 degrees then it should be OK.
If your squealing coincides with loss of volts at the meter, sure sounds like the alt is seizing.

200sportxj

I really dont know, just put it all back together old alternator and all and its not squeeling so we will see later this week

I DD it on the weekdays

5-90

Typical test for serpentine belt tightness is to grip the longest span between your fingertips - you should just be able to rotate it 90*. In the absence of a Krikit II gage (I need to get one...) that's the method I use.

However, bear in mind that your belt runs over considerably more than just the alternator pully. The crankshaft drive pully usually does not make noise, since the bearings it runs on are oil-film slipper bearings.

However, nearly every other pully uses some variety of ball bearings to run the shaft on, and any of them can start squealing on you.

If I have difficulty isolating the sound, there are two approaches I'll use:
- Remove the belt, then spin each pully individually by hand. However, this won't usually detect an early failure.
- Get out a mechanic's stethoscope (you don't have one? Why on Earth not?) and idle the engine. Touch the probe to the casing behind each accessory pully in turn, and to the hub of the idler pully (that hub doesn't spin.) You'll isolate the failed bearing rather quickly that way.

As you can guess, the second method is a lot less work and simpler - and will catch minor failures earlier.

If you don't have a mechanic's stethoscope, you can usually get one at Sears for ~$10 - and most locals as well. One may also be improvised with a length of rubber hose (fuel line or vacuum line will work) and a bit of metal in the end for a probe (a screw will work, as will some plain metal rod.) Stick the open end in your ear and check around - but I prefer the stethoscope, since it leaves both hands free (and has mechanical amplification, so you can hear quieter noises with it.)

Odds are good that it's the bearing in the idler pully going out - which is an easy fix, and runs about five bucks. Get a replacement bearing, then use a vice to press the old bearing out and the new one in. If you don't have the means, then you can probably get an idler pully assembly - if you go that route, I'd like to try to get the old pully from you.

200sportxj

Well I knew all of what you said lol.

I am a mechanic by trait aswell.... It just baffled me. Ive never had to mess with this type of tensioner. always had cars with the other types of tensioners, i Dunno ill drive it all week and see what happens