Heater Questions

[Benhoward384]

My heater was working fine on my 97 ZJ 5.2, I did a complete coolant flush on the engine yesterday and now I'm not getting hot air. I spliced into the heater inlet hose with a flushing tee and flushed the system that way. I have no leaks anywhere. I will get hot air for a second then it cools down and if I turn the nob to cold air it defintely blows cold and if I turn it back to heat I can feel the temperature change but it's defintely not blowing hot and the truck is getting up to temp. Also if I sit there and rev the thing real high I will get hotter air but at idle or driving around unless I'm at high rpm's the thing blows cold. I'm stumped.

 

[zukkev]

Was the heat fine before flushing???? You likely have an air bubble in the system, or the core is partially restricted....

 

[Hip]

find the high point and vent the system of all air.....

 

[Benhoward384]

Yes the heater worked completely fine before I flushed the system. Hip, I'm not understanding what you're telling me to do.

 

[zukkev]

Locate the highest point in the cooling system, and bleed the air from there...also, try removing the lines from the heater core, and reverse-flush the core....might be some scale restricting the inlet....

 

[Benhoward384]

Cool thanks I will try to reverse flush it

 

[Benhoward384]

May be stupid question but I have to ask. I back flushed the system through the inlet hose. Is back flushing the same as reverse flushing or is reverse flushing going through the other hose?

 

[Benhoward384]

And just to make sure I understand correctly if reverse flushing and back flushing the system. To reverse flush I splice into the other hose with a flushing T and run the hose water through it?

 

[zukkev]

Take both heater hoses off at the engine end, and flush the core both ways a few times...reinstall the hoses, then top off the system and bleed the air...

 

[WA-Wheeler]

Take both heater hoses off at the engine end, and flush the core both ways a few times...reinstall the hoses, then top off the system and bleed the air...

Exactly what i was going to suggest if zukkev did not beat me to it like he always does. :fawkdancesmiley: