1989 Max has a hint of heat when the heater is on high temp. The blower motor and fan are working fine. The temperature gauge goes to the normal position (about half way up) after five minutes driving. I checked on the two hoses going into the firewall that I believe go to the heater core unit, the top hose is hot, the bottom hose is hot but not as hot as the top hose. Does anyone have some ideas???

 

Plugged Heater core or evap?

 

http://www.cybrrpartspro.com/Chilton...H06_3_IDX.HTML

 

Are your controls set right? Like on recirculate instead of fresh air?

 

oohh good point

 

Air trapped in the heater core? There's a TSB regarding this...have you recently changed or lost coolant and added more?

 

definitely make sure that the radiator and overflow bottle are full.

 

Yeah.... what they said!