just had this problem with my 97. if your car blows alot of white smoke or has coolant in the oil it would be the head gasket which is usually the culprit to the no heat thing from what I've been told. in my case i got LUCKY. pull the front passenger side up on a curb start the car with the heat on high, take off the reservoir cap and keep filling with engine coolant as needed. rev the engine a little every couple minutes and watch the air bubbles come into the reservoir from the lower hose. now my friend you have "burped" the coolant system. if you still don't have heat or a blown head gasket check the interior floor and see if it is wet. then it would be a heater core.
good luck
the heater hoses usually lead away from the thermostat and go into the fire wall. On the other side of the firewall is the heater core. the top hose on the radiator goes into the thermostat most of the time
Sounds As If You Need To Replace It. There Isn`t Much Of A Test To See If It Is Working Unless You Remove It. Replace It + Any Radiator, Heater Hoses, Bypass Hose Also.
On a 4.0L, yes one of the heater hoses does.
Heater works fine in my Wrangler! Check the thermostat or the hoses or heater core might be plugged. The thermostat is easiest ^ cheapest to change so start there.
The thermostat on a straight 6, 4 litter Jeep Cherokee is located on the very front of the engine. Just follow the valve cover to the front of the engine and you will see the thermostat housing it has two heater hoses coming out of it (one to the radiator and one to the heater core). Simply take out the bolts holding the housing on and remove the heater hoses and the thermostat will pry right out.
no heat can be caused by,blocked heater core insufficient coolant in engine blocked heater hoses from engine to heater core bad heater thermostat bad thermostat in engine bad heater control switch
Check your thermostat. Probably stuck open.
heater core plugged or air locked check to see if hoses going to heater core are hot
the heater core water pump hoses including the heater hoses
the heater core could be stopped up, or could be low of antifreeze, or the thermostat could be stuck open
Thermostat stuck open, if older car possibly clogged heater core- when run at oper temp the hoses going into/out of heater core be sure one is very hot - start with thermostat $$$ cheap & easier than a heater core problem!
The heater core may be plugged. With the engine running and fully warmed up, feel both of the heater hoses with your hands. If one hose is hot and the other is luke warm or cold, the heater is plugged in which case you can try flushing the heater core. If both hoses are hot, the temp blend door acuator behind the dash assembly is broken. If both hoses are cold, replace the thermostat again and be sure the cooling system is full.