Seen a lot of people over the years with over heating problems with their second gens. Seen that they replace the thermostats, flush systems, replace water pumps with no fix. Just want to mention all three of second gens that I owned had overheating problems do to a bad tension pulley assembly which would let the belt loose enough to slip on the water pump. Usually can hear the belts squealing or watch the tension pulley assembly jump while engine is running.

just my two cents worth of experience hope maybe it can help someone save a penny.

 

Thanks for the post. I've started monitoring the "New Posts" section so I can gather new hints and knowledge such as what you shared.

I've replaced my tensioner a several years ago but now I am hearing a sort of squealing, a lower pitched one, that goes with the engine speed. It also only happens now and then.

I try to pop the hood and try to find the source but I cannot locate it. Also it often is gone by the time I get to the front.

BUT, I have noticed my tensioner oscillating/jumping back and forth while the engine is running. According to my manual, it is not swung out far enough to indicate a stretched belt though.

Perhaps what I'm hearing is originating with the tensioner?

 

I have noticed my tensioner oscillating/jumping back and forth while the engine is running. According to my manual, it is not swung out far enough to indicate a stretched belt though.
I believe this is normal, both my blazes do this

 

I have a second gen Grand Cherokee and typically the source of this noise is actually the idler pulley bearing. You can buy a whole new pulley and bearing, but if you have a shop press, all you need is a 203ff alternator bearing and a little Loctite.

Interestingly enough, both my Grand and Blazer use this bearing. All parts stores have them.

 

If I seen a swinging serpentine belt, I'd remove it (3/8 release socket within a belt tensioner) and manually check for a worn off (loose) bearings. That would let me know whether the problem lays in a belt tension or a worn off bearing.
Just my 0.03$

 

could also be a weak belt tensioner spring.

 

Thanks Mike. I can't believe I did not think to do that for myself yet! I'll try to get to that today.