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HELP with 1990 overheating!!!

680 views 2 replies 3 participants last post by  sleddy5 
#1 ·
I have a 1990 Cherokee and i bought it about 2 weeks ago. The cooling system was fine when i bought it and it hovered right about 210*. Only untill last weekend the whole cooling system went haywire. I first noticed it happen when i was driveing above 60 on a hot day. I drove for about 15 min. and when i popped the hood, orange coolant was gushing out of the radiator fill bottle. I let it all come out and then i filled it back up with tap water. Iwas fine for about a week and then i was only going about 25-30 for like 3 miles, when the temperature guage jumped from 208 to about 260 in like 3 sec. i put the heat on and ran it untill i got home. I replaced the upper radio hose and nothing happened. It would still get extremely hot and gush out of the fill bottle. now there is cooland coming from what looks like the water pump, but it might also be the conection at the lower radiator hose. please help me and remember that its a closed system!!!
 
#2 ·
My opinion, start from scratch.

Get a new 195 Tstat, flush the system out, check the connections on the hoses. Once the Tstat has been replaced and the coolant replaced with the Prestone green coolant (50/50 mix of DISTILLED WATER). Crank it up and refill it through the overflow botte. The once it has stopped, Burp the cooling system.

http://www.lunghd.com/Tech_Articles/Cooling/BurpAirMod.htm
http://www.jeepforum.com/forum/show...ght=burb+system

If the system over heats at idle or low speed but cools down at faster speeds then the factory clutch on the mech fan needs to be replaced.

If, when all this is done, it leaks collant from the bottom of the water pump, it's time for a new one:
http://www.jeepin.com/features/waterpump/index.asp
 
#3 ·
well I have a 90 and have had similar problems. I would recommend checking all your hoses for possible leak sites and replacing your thermostat. I had problems with the new thermostat fitting so I ended up with a 185* that did fit and it works great. I dont have the overflow tank in mine since it was upgraded to the newer style cooling system. I dont see why you couldnt bypass it with yours though, just use a brass connector from menardsand 4 hose clamps (2 on each side to be safe). Make sure you get all the air out of the system when you fill it up by adding coolant, capping starting up till it warms but shut it off before it gets too hot then let it cool and pull the cap off the radiator to let the air out and add more coolant, repeat till you get all the air out and see if you have any more problems. If it still overheats it could be something more serious like your waterpump.
hope this helps
 
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