Homotor

i have a 92 honda civic, and my heater is not blowing hot... a/c and everything else works and blows fine but when i change it to hot to blow heat it just blows air... can someone tell me what might be wrong?? thanks...

jdm602

the cable that goes to the valve on the heater hose in the engine bay or under the dash may have come off. go check.

H_Bliss

Check your thermostat. 99% of the time, it's that. And it's also a very quick and easy fix.

fastrxu

The coolant thermostat? ^^^

Homotor

ive checked the cable it seems to be connected and working, just no heat?? i will try changing out the thermostat if that doesn't work im out of options, thanks for your help guys...

kyden

you might have a blocked heater core.

as for the thermostat, does the engine come up to normal temp?

fcm

Ditto the above^^^.

If engine temp is OK it is either a restriction or the valve is not working, easy enough to check.
Once engine temp is up to normal, feel both the heater core hoses when heat is on, both hoses should be hot, if there is room check hose temp on both sides of valve, if one side is hooter/cooler then other side, replace the valve, [it's defective].

If heater core is plugged you may be able to flush it out, disconnect both heater core hoses and connect up a garden hose to the heater cores return side and turn on the water and flush out the core, you can even "break" stuff free by switching the garden hose back and forth between the inlet and outlet of the core. 94