XJ TENN

My heater is not putting out hot air.

I did a coolant flush, replaced the radiator, and replaced the thermostat. Ten minutes into the test drive the heater stopped putting out hot air.

All door actuators on the heater box are operating as is the heater control valve. Coolant is good and full. Engine operating temp is perfect.

What am I missing?

Why no hot air?

JPXJMOAB

Did you reverse flush the heater core?

XJ TENN

was planning to in a few minutes. had to thaw out the garden hose in the sun

XJ TENN

just to check on my thinking, coolant runs from the thermostat housing to the bottom inlet on the heater core and back to the waterpump, correct?

JPXJMOAB

haha I feel ya.. It was -15 here this morning! Anyway, try a reverse flush. However beware that this can cause it to leak if there is any crud in there plugging holes. The way I look at it.. It either works or it doesn't, if it leaks and doesn't work you'll need a new one anyway right? Let me know what happens.

XJ TENN

It worked I have heat.

some pretty nasty stuff came out of there.

gpXJ

Yup I just did this to both my XJ and WJ 2 days ago. They were both nasty, though the XJ was worse. Heat is blazing now!

JPXJMOAB

awesome! Glad to hear it!