i have a 1988 cherokee pioneer with a 4.0. we had a problem of the jeep having a small amount of antifreeze showing up on the garage floor, so i started investigating to see where it was coming from I found out the antifreeze resevoir had a crack in the bottom. So I replaced that and a new cap, while I was taking the bottom hose off of the resevoir the heat valve broke, so I replaced that. Refilled everything, Then not long after that it started overheating, so I burped the system, to no avail, I then replaced the thermostat, it still didn't help, so I replaced the water pump. Now the opposite problem has happened, the jeep will not heat up above about 120 degrees. I thought it may be the thermostat.(faulty from the factory) wrong. So now i have a jeep that will not warm up and my wife is constantly on me to get it fixed. As it is her everyday driver and living in N. Idaho in the mountains heat is a must. So please help bring the harmony back to our household.

HI, IF YOU EMAIL DIRECT AT jeepman600@aol.com I'LL SEND ARTICLES ON COOLING SYSTEMS DALE
jeepman600@aol.com

did you refill the reservoir with coolant? If there is only a mininum amount in there, you're not getting enough coolant through the heating tubes. Or your therometer could be reversed, but doubtful.
good luck on the harmony thing.

i have looked all over and think i have checked almost everything. i am just at wits end. this jeep will just not get warm inside or by the temp guage.

just had another thought - i had a 86 cherokee with a problem like it and just remembered - i took apart the hoses leading into the heating unit to find that 1 of the steel hoses that went into the firewall had bent into a 'c' shape. This probably happened by the clamp being tightened to much at one time.

Took me days to figure that one out.

hope it helps.

hit a hardware store and buy a (water hose repair piece) female end,
disconnect the hoses going into the firewall (to the heater core) install the hose end and hook up to a water hose - turn the water on full - you will see alot of brown water coming out of the other hose once it runs clear turn off the water and disconnect then put the hose end on the other line, run the water until you see clear again. this will unplug/clean your heater core out - I have to do it with my 87 XJ about once a year or I do not get any heat.

good luck
gunny

have the cooling system flushed