hi i recently bought m y girl a 1996 grand cherokee. haveing a issue with the cooling system that i dont really understand.

its about 15 here at night and there is no heat

the truck can run for an hour and both heater hoses and upper rad hose are just luke warm not hot.

there are no leaks that i can see. for some reason there isnt any preasure there rad cap can be removed and the coolant in there isnt hot either...

here are things ive done so far

couple months ago replaced radiator due to crackrd side tank. the coolant that was in there was nasty looked like mud so flushed what i could.

2 weeks ago replaced water pump due to leaking weep hole. heat still workd for bout 2 days after te water pump replacement. the coolant was sill kinda dirty but way better than what it was. idk what it is i am leaning torwards a heater core though.

oh and by the way the truck does not overheat at least according to the guage.
thanks

 

Could be a heater core blockage of some sort but could also be the Gosh-Darn Blend Doors went out on you.

You said that you flushed it and it was kinda muddy lookin. Its possible that you dislodged a big clump in there somewhere that worked its way into the heater core. However, replacing a heater core is no joke, fairly straight forward but a major PITA to get to as it is an involved undertaking.

Best advice i can give is to eliminate all else before jumping to the core.

do you have the 6 or the V8?

 

Could be a t-stat stuck open.

 

thanks guys. it has the 6 cylinar in it. i was goin to try the thermostat just cause it is a cheap thing but the guage does go up to normal temp that is whats throwing me off. think i will try taking the heater core hoses off and flushing it see if i get anything else out. would the heater core affect the temp of the top radiator hose causeing it not to get hot? ive replaced the heater core in a few older rams 97 98 and 01 but never a cherokee. it wasnt as involved in the trucks i dont think just losend the dash and slid it back a little and it was right there.

thanks agian for the help

 

The heater core should not affect the temp of the radiator hoses. Not to insult your IQ but Thermostats are supposed to cycle between open and closed positions to regulate coolant flow to the radiator which in turn regulates the temp in the engine. I have seen japanese cars with inline 6 cylinder engines with smaller radiators than Grand Cherokee's have. With that said, GC's have rather large radiators for a 6. This is a good thing in the summer months. However in the winter when it's cold, it becomes too efficient. If the Thermostat gets stuck in open, meaning it no longer cycles between open and closed, coolant flows thru the radiator and cools off twice as fast in the winter.

It sounds like you may have more than one problem. If the gauge is saying the engine is warming up but your not getting heat it may be something else.

However, one thing at a time. Change your T-stat ASAP.

 

ok thanks i will try to change that this weekend and see what happens and while iam at it guess i will try flushing the heater core too..

 

Flush the heater core in BOTH directions a couple of times. If your coolant was muddy before, you might try running some CLR or Limeaway through the system for a couple of days. You would be astonished with what comes out!

 

ok well flushed the heater core out and nothing came out it flowed fine.. i did notice that the fan is always running it should only run when hot right?? seems like the clutch may be bad thats what iam thinking.

 

Have you replaced the t-stat yet??? The heater core is a massive PITA to get to, try it out...then go from there.

 

no i have not tried that yet do to the fact that it still gets up to normal temp it just takes a while. i thought bout changing it though cause its cheap and easy. i really dont think its the core anymor cause i flushed it with a garden hose and it flowed great. plus the water on the otherside was clear.

how do these clutch fans work. are they like electric fans where they come on at a certian temp? if so i think that might be my issue cause it runs no matter what from when the jeep starts till i turn it off

was thinking maybe the blend door too but idk


thanks

 

t/stat would be the first place i would start. on all 3 of the jeeps ive owned the t/stat has fallen apart about 120-140k lol. i bought a new one a week ago while i did my radiator for 2.65$ lol. they are super cheap.

 

ok thanks i will give that a shot. hopefully this weekend