how can i get more heat

[hilljob26]

well,my 72 is not the warmest thing to get into every morning,but its all i got,anyway,i have a 195 thermostat,4-core radiator,new coolant,new heater core,but it does not feel very warm in the cab at all,i think i have my heater core hoses plumbed backwards,would that really that much difference,or is it the fact that i have 2 12 inch cooling fans running,any advice would be great.mike

[Bowtie67]

I am not sure if your fans are running consistantly and they shouldnt be, one of the things you can do during the cool weather is to block off some of the radiator in the front, Take a piece of cardboard the width of the radiator and cut a V-shape/circle/square in it to allow some air like you see the big truckers due during the winter and that should get you some warmer coolant to the heater core, it also doesnt help having the hoses reversed. I have a bit of the same issue in mine, I have a new heater corp & hoses are correct, and I have a big aluminum radiator with a 185 thermastat and it doesnt get very warm inside either during cold days, but for me it's not an issue becasue I don't drive it during the winter.

[Palf70Step]

The water flow does effect things. How much I am not real sure. I would try running the plumbing in the correct geometry. More than likely your heater core is plugged and your not getting the full effect. Both of mine will melt you out in a very short while. Another thing for nothern climate folks, is our cabs are not insulated worth a s--t, thus the heaters (and AC in south) has to work its butt off to do its job. Having good door seals and extra insualtion in the cab will help.

I'd almost bet in your case though that you have a bad heater core.

[Longhorn Man]

flow direction won't fix a thing.
You need to grab the wife's turkey thermomter and shove it down the defroster vent, and see what the air temp is when the truck is fully warmed up.
Low air temp;
clogged heater core, eithyer internally or ecternally... new ones are cheap.
control assembly not letting the temp selector move all the way.
Heater 'door' inside box is not working properly, damaged bad seals.. ect.
Low coolant temp. If your fans are on all the time, then you need to finish your conversion and get a temp controlled switch in there. your fan motors will not last long being on all the time.

High heater air temp....cab still cold;
cab corners/floor has holes, letting in bitt loads of heat. Plug the holes with tape or rags ow what ever.
Look for holes up on the firewall... like the clutch rod hole.
door seals or poorly mounted doors.

[Bill72BB]

What Andy said , I found my Heater door was sticking inside the box .

[Zonaman]

These trucks aren't insulated very well. If everything else is OK. You might consider something like "The Insulator" by Bonded Logic. Poor weather stripping might also suck alot of heat away.

[Americanrider]

I just finished a rebuild on my outter heater box. When I pulled the motor/fan assembly I found that the cage fan had a few broken (plastic) blades from sticks & garbage falling through the cowl. I stuck a garden hose down each side of the cowling a flushed out years worth of pine needles, mud & leaves. I lubed the inner cable and flappers and sealed the box to the fiewall w/Black RTV. Used a motor/fan assy from a non-AC '76 GMC truck I parted out since it had a metal cage fan, it was a perfect fit and everything works better now.
The SBC Heater Hose route is Water pump to Top, Manifold to Bottom

[hilljob26]

it bet it has to do w/ the door inside,it has a a/c control panel,but a non a/c box,how can i make sure it is operating properly.....mike

[LUV2XCLR8]

Originally Posted by Palf70Step

I'd almost bet in your case though that you have a bad heater core.

This gets my vote, my 70 would run me plum out of it, just like a sauna

[hilljob26]

but its a brand new heater core,ya think i should blow through with some air,i mean,i am going to redue the hoses anyway......mike

[Gordo]

The heater hoses should give you a clue.
With the engine running and fully warmed up, hand feel the heater hoses. First the hose feeding the heater (from the intake), then the return hose (to the water pump or radiator) if the heater core and thermostat are healthy they should both be hot and almost the same temp, the feed hose slightly hotter. If that's true the core is probably okay and you have a duct problem. If the feed hose is hot/semi hot and the return is cold/semi warm then I would suspect a circulation problem such as a plugged core. If the feed and return hose is only warm, I would suspect the thermostat is stuck open/faultly. With fans running or not the thermostat should hold back the coolant in the block until the coolant temp reaches 195.

[Bill72BB]

Originally Posted by hilljob26

it bet it has to do w/ the door inside,it has a a/c control panel,but a non a/c box,how can i make sure it is operating properly.....mike

Mike ; when its hot check both hoses going to thre heater core and make sure they are the same temp . if the return hose is cooler water is no flowing thru the core .
Do you have a vacuum control valve on the heater input line to the core ?
Here is a pic of the Heater control valve on BB .

[hilljob26]

well,i switched the heater core hoses,and messed around with the knobs on the heater control,and that thing is freakin HOT,that rocks,i appreciate all your guys help......mike

[Palf70Step]

Originally Posted by hilljob26

well,i switched the heater core hoses,and messed around with the knobs on the heater control,and that thing is freakin HOT,that rocks,i appreciate all your guys help......mike

Wait till summer, you may thing we stink then for getting you so much heat.

Glad it worked out.

[c10chevy69]

Easy fix for summer: put a valve inline within the inlet hose. I have one on mine and it so nice not to have to deal with engine heat on a 98+ degree day.

[teeitup]

Mike, can't help on the heat deal but did you ever find any mirror arms, I finally found the set I had here. Thanks Randy