heat not getting hot enough in my '66 C10 help!

[yellow400ex05]

I just bought my '66 C10 and plan to use it as a daily driver but so far the heat sucks in this truck. i know its old but it only blows warm air, which pretty much barely gets the truck warm. what could be the cause to this? should I back flush the heater? or would that not be good for this truck?

[DoubleL]

Could be a bad thermostat.

[TopFuel1966]

Could be no thermostat.

[bk2life]

Originally Posted by yellow400ex05

should I back flush the heater?

yes flush the cooling system, replace the thermostat. while flushing it out, pull the hoses to the heater core and make sure the hose water going in is coming out. if not, it's clogged/plugged. but if the water going in comes out just fine then it's your thermostat.

all in all about 30 mins of work, and 25 bucks for t-stat, gasket and some anti-freeze..

let us know what'cha find out

[yellow400ex05]

which would likely be the main problem?

[yellow400ex05]

i want to just try one or the other but I'm starting to think you guys may think the thermostat is the main common issue here.

[tincan1966]

Something to help diagnose- what is the engine temp? if it is normal and you have little heat, then I'd suspect a possible heater core restriction. if engine temp is lower than normal- then possibly a thermostat.

Like mentioned previously, it's a maintenance thing, just flush the system, replace the thermostat. Not much time involved and a cheap item to do.
if you want to take a real simple approach, remove the heater hoses from the core, connect a garden hose to one, them turn on the water, and see what you have for flow out the other one, and how dirty it is. From there you will know what needs done.
Either way, if you flush the system correctly, you'll need to remove the t-stat and refill system with new antifreeeze anyway.

[rs74]

Originally Posted by tincan1966

Something to help diagnose- what is the engine temp? if it is normal and you have little heat, then I'd suspect a possible heater core restriction. if engine temp is lower than normal- then possibly a thermostat.

Like mentioned previously, it's a maintenance thing, just flush the system, replace the thermostat. Not much time involved and a cheap item to do.
if you want to take a real simple approach, remove the heater hoses from the core, connect a garden hose to one, them turn on the water, and see what you have for flow out the other one, and how dirty it is. From there you will know what needs done.
Either way, if you flush the system correctly, you'll need to remove the t-stat and refill system with new antifreeeze anyway.

I will second this. No more time and money that it would take then do them both right then. I always flush the heater core from both directions a couple of times back and forth. Just to make sure. Replace the antifreeze as you dont know how old it is. In a matter of minutes then you should be ready to go. Unless the heater core is plugged really bad.

[61K10]

do all of above--if still having no heat. what size radiator? 2/3 or 4 core? I had a 69 (350 eng) with a big 4 core rad, had to put a piece of cardboard in front of the rad in winter to get some heat in 30deg weather was using a 180 thermostat.

[yellow400ex05]

well i checked the coolant temp while it was running, was at 165 degrees so i'll start with a 180 t-stat

[dracko]

i live up in canada and drive my 64 daily, it gets real cold. I run a 190 t-stat and it gets toasty warm in the cab. also the cardboard helps. Just grab the in/out coolant hoses and make sure they're both getting hot.

[sharkskinman]

Bump

65 250 185* stat guage at head cooling temp reads 210* normally..
Hot water in smaller hose
Not hot in bigger hose

Going to try garden hose trick and change stat

Temp here in new Orleans variates so much here..

[Indian113]

sharkskinman, I'll bet your heater core has clogged fins due to mouse nest or leaves. You may have to take it apart and clean or replace core.

[sharkskinman]

Put old one back in after newer one had leak.. No nests in there but???
Maybe some sealant of some sort got in there.. When I got it no stat and wouldn't warm up.. Changed that out and current one works(pulled out and watched it close)