05 Uplander, no heat

[grt]

My van blows cold air until the rpms climb up and then i get a bit of heat out of the dash vents but still cold air out of the floor vents. The engine temp is good, heats up fast so thermostat is not the problem. Sounds like this might be common with these vans but I've yet to find a solution

[aleekat]

No nothing about an Uplander but. Normally heater core stuff. Once up to temp with heater on full hot, feel the heater core hoses that go into the firewall. If one is noticeable cooler, then I would try back flushing the heater core.(partially clogged) If they both both feel hot, then maybe a blend door issue.

[Tech II]

Agree with Kat.....make sure coolant level in reservoir AND radiator have not dropped creating an air pocket....then check heater core hoses, that BOTH are hot.....if they are could be a temp door problem.....if one is much cooler, then try a reverse flush like Kat said....

Also, some of these vans had an auxiliary coolant pump....not sure if this one does......it is located under the cross brace in the engine compartment on the driver's side...

[grt]

How do i do a reverse flush?

[aleekat]

youtube has tons of videos on how to flush heater core.

[grt]

So both heater hoses are hot and all the hvac doors are working fine, still blowing cold air however. I'm stumped

[Tech II]

If both heater core hoses are hot, and by that I mean the same temp, not one hotter than the other....then it has to be a temp door problem.....if the actuator to the temp door is moving, then the linkage to the temp door is broken....

[grt]

The temp doors all seem to be working and are blowing air to the correct places but its cold air, could the heater core be plugged? I noticed a peanut butter like substance on the rad cap and on the top of the rad spout

[grt]

Now i was playing around with the temp dial and all of a sudden it started shooting out heat but still seemed to blow cold air through the floor vents