Just bought a 1987 Dodge b150 and the heat is inop. Blower works fine, I flushed the heater core with just water and to my surprise there was no rust colored water or much sediment at all which seems strange for a 30+ year old vehicle. Ive heard some theories that even though the heater core was running clear after no time at all(i did it both ways twice for the record) That it could still be clogged and it is letting water bypass through the tank without actually going through the fins. this seems unlikely to me but hey you never know.

At first i thought one hose was hot and one cold but i think i was just feeling heat come off the engine it sort of hard to tell and im not sure. I also noticed a lever on the passenger side of the heater box not hooked to anything but there didnt appear to be any unhooked cables near it, not sure if that matters or not.

Just looking for advice on the next step until my service manual arrives in the mail. Thank you.

 

I don't know if the 87 still used the valve in the heater hose but it was hooked to a lever on the dash. This controlled heat it might be diferant with AC.

 

It does not appear to have the in line valve. the valve is in the heater box and the only thing exposed is a lever that is hooked to the the cold/warm selector in the cab.

I shouldv'e also mentioned that i checked the rad, it is filled to the top even when the engine is running, i also topped off the reservoir and there should be plenty of coolant in the system. i tried to purge any air by squeezing the upper rad hose repeatedly both with the rad cap on and off. didn't seem to get much air. Also tried moving both levers manually and didnt appear to do anything, I heard two bumps when i actuated the heat valve which i think means its operational. Air would make sense though maybe I'm not bleeding it right. Also maybe worth noting, the thermostat never sems to go past about an 8th of the way up and not at all when driving, I actually thought it was bad when i drove it home.

 

It could be that the thermostat is not working properly or there is not one installed but there should be a way of regulating the heat in the heater.

 

So I went ahead and replaced the thermostat today as well as the housing. glad i did the old iron one was in rough shape. However it did nothing for the heat. I let the van warm up for a solid 20 minutes which should be more than enough for any car.

I can confirm now that both heater core hoses are cold. I flushed it out with water already so i know it gets flow, i know the hoses are hooked up correctly, so i'm kind of at a loss as to what it could be now.