my 1992 mpv 3.0 L V6 has no heat at the front but the back has heat. i change my thermostat and still the same. next step i disconnected the front heater and blow some air into the core thinking maybe it's clogged up and still no heat at the front but the back still unchange. after this i disconnected the back heater and hooked up only the front just to find out maybe not enough pressure still the same. some people say it could be the water pump so i did replace my water pump and at the same time the timing belt as well. still no heat. i'm still confused don't know where to go from here. any idea would be appreciated. thanks

 

Probably a door flap not opening.Check the door operations in the dash.

 

thanks for your reply. are you talking about the temp selector that has an aircraft cable attached. it seems to be working because everytime i move the selector the damper moves as well. why because i took some of the dashboard panel apart and i can see it moves

 

I have the same problem... The problem has gotten worse slowly for the last couple years. I am down to thinking that the heater core needs to be replaced. I have taken my dash apart and it doesn't appear too tough to do. Is there a trick to ensure I get all the air out of the lines.

 

If the core isn't plugged and the airflow flap is opening, then there must be a problem with the coolant valve feeding your front heater core.