Why am I getting only luke warm air from my Jeep Cherokee heater?

[Jim]

I have a 98 Jeep Cherokee, 6 cyl w/107K miles. Only getting luke warm air from the heater. Flushed the cooling system and later the heater heater core sperately. Not a lot of flow through the core and some back pressure when a blew through the inlet hose (with the outlet hose disconnected also) but maybe this is because of normal restriction in the core. The temp control switch and solenoid seem to be ok (shaft moves with I adjust the switch). The heater hoses don't get hot. Also doesn't seem like a lot of motion of the coolant when I run the engine with the radiator cap off but there is some. Wondering if maybe the water pump is weak although the temp guage reads normal. Replaced a leaky radiator recently but this problem was before and after that. Would appreciate any suggestions.

Thanks

 

[nosdda]

You have an air lock in the coolant system, probably the heater matrix. Did you bleed the air from the system after flushing the system???

 

[Bill]

There are a few possibilities, the heater core could be blocked, there may be an air pocket in the cooling system, the thermostat could be stuck open not allowing the coolant to heat up enough or your blend door may not function.

Double check the coolant level, if its ok then try flushing out the heater core with a hose. Those are some easy things to start with.