I will preface this by stating that I am not a Jeep guy, so the answer may be common knowledge to some.

My wife's DD is an 01 Jeep Cherokee Classic. Over the summer I had to change the radiator due to a leak. I also changed the tstat and water pump at that time. She told me about a week ago that the heat doesn't work anymore (heat worked fine last winter). I did some research and found the whole blend door thing. I checked that out. The blend door motor works just fine. I removed it and actuated the blend door by hand. It also works fine.

Am I to understand that the heater core has coolant flowing at all times and is just shut off by the blend door? If that is the case, the core has to be clogged either by junk or air. Are air pockets common when refilling the cooling system? Is there a trick to avoid air in the system while filling? I am going to use some Prestone Super Flush next week as a last ditch effort before I even think about pulling the dash assembly to address a possible clogged heater core.

Any help will be awesome.

check your heater hose in and out of heater core to see if both are same temp. If you have a clogged heater core (common problem) you may get lucky and be able to clean it out by back flushing it.

There is definitely a difference top to bottom. That is how I determined something is blocking the heater core. These things do not have a heater control valve do they?

There is definitely a difference top to bottom. That is how I determined something is blocking the heater core. These things do not have a heater control valve do they?


My 1992 4.0L does, but it is in the heater hose going into the heater core...

There is definitely no valve under the hood. I believe that changed in 98 or 99.