Help My Jeep is overheating.

[kenjeepfreak]

I have a 89 with a 4.2L in it. I have a problem that I cant figure out. I'll be rolling down the road and it does not heat up then all of the sudden it gets real hot like around 220 or so. I have a 195 thermostat in it. I replaced the temp sending unit a couple of months ago cause I had a problem with it then. It has been running nice and cool since then, but a couple of days ago that problem came back. I flushed the radiator out a filled it with the proper amount of antifreeze, I just dont know what else to do...

PLEASE HELP!!!!!!!!!

 

[jps4jeep]

There are a couple of thing you can look into:
T stat, make sure it is not jamming shut
hoses, make sure they are not binding on anything
Water pump, is it original? what condition is it in. There are some corrosion issue that come into play when you have an aluminum part and a steel part contacting each other in the presence of antifreeze. I believe it is a "electorstatic corrosion" but I can't really remember
Johnny

 

[laneiac]

I had the same type of problem, threw in a 180 thermostat and a new water pump, replaced all the factory hoses clamps with good screw tight clamps, and voila, ran like it was new.

 

[Tug-n-pull]

also check your fan clutch! tug

 

[jeepin916]

make sure u dont have any air in the system. and check for a restriction in the radiator thats stoping the coolant from flowwing properly

 

[hi_c]

Make sure your coolant reservoir is full.

 

[hi_c]

test

 

[shutterman400ex]

i had the same problem i flushed the radiator and chagend thermostat. it still was overheating. then my friend came over and he noticed that it was the fan clucth

 

[shutterman400ex]

changed it and there was no overheating eversince