86 chevy no heat

meatheadwes

meatheadwes

Well-Known Member
Joined
Nov 8, 2009
Location
kings mountain
ive got an 86 k1500 i have no heat at all no defrost or nothing and im getting tired of wiping the windshield while cruising down the road. any input on my problem? i aint had the truck to long and i have no leaks form the heater core or nothin and my fan dos come on and blow but no heat.
 
With engine warmed up check heater hoses. Both should be warm. There should be three doors in heater box. One for temperature. It allows air to flow across heater core. 2nd door directs air up or down for heat or defrost. 3rd door allows outside air to enter( vent) If you need more info Ill go look at one of mine
 
i figured it out i checked the thermostat housing. the thermostat wasn't in the correct, the previous owner put an aftermarket housing on it and the hole was to big causing the thermostat to lift up and water to go around it. didnt tear into till late so imma run to pull a part and grab a housing in the mornin and hopefully i've got my fingers crossed this will solve the problem
 
Yep, you'll have about 8 months to check it out!
Haha> A friend of mine was driving his Old chevy truck back from the beach, & blew a head gasket. He poured block sealer in it, & made it home [Charlotte] Then complained of no heat but engine was hot! I got him to flush the core, & block, & after he saw what came out, he took the radiator to a shop. Got everything back together, & it Flowed so good, it wouldn't warm up! He had taken the thermostat out a couple years ago, when it was running hot!:lol:
 
my thermostat houseing was replaced with a aftermarket p.o.s from o reillys and the hole was to big in the houseing the thermostat was flipped on its side in the neck of the houseing thought that was the problem but it wasnt
 
There should be a valve in line with the hose for in coming water to the heater core, check to make sure that valve is in fact open and not packed solid with, mud, rust, sealer..ect. btw the valve will be under the hood, not sure on that year if it is vac. Operated or cable
 
Should look something like this...
download.jpg
 
I had the heater box out of my 77 K10 this past winter so I thought I would put a heater core in it since it was already out. I get one and it's aluminum. Start the truck up. No heat. Air is barely warm. Put the old copper unit back in and it would almost burn your hand in front of the vent. The aluminum core had such small air passages that nothing was going through it. Even sealed around the outside with foam. Look at the tubes coming off of your core. If they're aluminum then that could be your problem.
 
My wife & I dated while driving my '70 Suburban w/ little to no heat, she damn near froze on dates (blanket, ear muffs, but no complaints).

After getting another truck, I replaced the heater core & it will run you out - she was not laughing after freezing all those years.

Stop leak kills the heater core....assuming the coolant is reaching the core.
 
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