Heater not working

[BJH324JH]

What on earth could stop my heater from working? Thermostat is good,just replaced it. Could it be the water pump? Rusty radiator? I also pressure checked the radiator, no leaks.

[silverjoel]

Could be as simple as an air bubble trapped in the system or a clogged heater core. I like to use the radiator fill funnels when flushing/changing the chilling system. It's best to squeeze the upper radiator hose to get out all of the air bubbles and do some revving.

You could also flush the heater core by itself as it's pretty accessible.

[geezer101]

Heater valve is ok? Heater control linkages are all clamped down and actuating properly? Might be something simple. I've seen some pretty funky heater cores. If you suspect it's a clogged core, mix up a batch of citric acid powder and hot water and run it through the core. I rigged up a flush system from a pressure cleaner that has a bad pressure regulator in it and continuously ran citric acid wash through a few different cores. Either the citric acid wash dissolved all the calcium, sediment and rust flakes that were trapped in them or they sprang leaks from already being corroded out. The most thorough way is to take out the entire heater assembly and strip it down and bath the core, then jam a garden hose on it and flush from both directions. Yes it's a PITA job but not only does it ensure you can really clear out the heater core, but it gives you a chance to clean all the dirt and junk out of the casings, replace foam seals and adjust all the linkages to get it working and looking like new. It's not so bad to do if you don't have A/C.

[BJH324JH]

Thanks guys. Will try out your suggestions.

[BJH324JH]

Could be as simple as an air bubble trapped in the system or a clogged heater core. I like to use the radiator fill funnels when flushing/changing the chilling system. It's best to squeeze the upper radiator hose to get out all of the air bubbles and do some revving.

You could also flush the heater core by itself as it's pretty accessible.

LATE UPDATE (TUE, DEC 6, 2022 10:38 P.M.) :

It was exactly that, an air bubble! The system had been flushed multiple times with corrosion removing radiator flushing chemicals. So, it couldn't have been a clogged radiator or heater core. I simply didn't know how to purge the coolant system of air, which is why I had no hot air. Now that I know how to purge the coolant system of air, I have a warm heater.

THANK YOU GUYS FOR THE TIPS! BTW, I sit in my truck with the nice warm heater on as I type this. Yup, I'm cozy. :) 49° Outside

[xboxrox]

49 F degrees OMG in California..! All good now tho, good job man..!

Aloha BJH324JH <--- Because Japan Held 324 meetings to make a Mitsubishi compact truck, Japan Hiccuped..? :shrug:

[geezer101]

Like all worthwhile endeavors, it took some time but you got there. Nice job :thumbup:

[BJH324JH]

49 F degrees OMG in California..! All good now tho, good job man..!

Aloha BJH324JH <--- Because Japan Held 324 meetings to make a Mitsubishi compact truck, Japan Hiccuped..? :shrug:

I didn't want to think of a username so I just slammed the keyboard keys and that username came up. Hahah very creative though.