i cant get my heater to work new fan,thermostat , raidiator,but still no heat and new heater core .wondering if you guys have any ideas.

 

Both heater hoses getting hot, and did the new core fit in the box correctly with all the foam back in the correct spots? My '78 is really weak, too, I'm ready to pull the box back out and try to figure it out - the blend door arm is moving properly on the outside, and 1 hose is hot, the other slightly cooler, good air volume at the defrost, but it doesn't blow much heat at all. Keeps the windows clear, but you wear gloves... I'm thinking I'm bypassing some air somewhere, either pulling it past the blend door or around the heater core. It got a new core maybe 4 years ago (mine's a HO), and I thought I got all the foam and such back in........

Another thing is make sure the cab is sealed up good - there isn't a recirc. option on these cabs, it's all outside air through the heater. If you're losing a pile of air through missing window tracks, clutch pedal boots, door seals, etc., it will pull air out of the cab and through the heater faster than it's supposed to, overwhelming the heater and not making the high temp. air it should. Does yours make any heat sitting still after the pickup is warmed up?

 

do you have factory AC? if so is the vacuum controlled water valve opening under the hood (inline with one of the heater hoses)?

 

Is the fan turning on? If not check the 30 amp fuse and then the switch

 

Make sure the heater core is not air locked. A good practice is to fill the heater core with coolant once it is installed.

 

i had to seal up the vent going to the pass side seems to helped it out with heat issue thanks guys.

 

found out the problem gasket seal had the pipe on top of thermo stopped up solid.