I live in michigan and its 17 degrees right now. my heat comes on but very lightly, I have a stock h22a 5/speed. so far I checked out the heater core and its clean blows through easily. I put a stock thermostat in and still the heat just doesnt come out hot, just warm enough to defrost half the windshield and a small portion of the door windows. please help I hate seeing my 3 year old shaking.

 

Does your valve on the firewall (in the engine bay) open all the way when you slide the heater control over to hot?

 

Bump on shivering. Flushed the cooling system at home, then the garage did it again after I just had an engine swap done... still only luke warm heat. If it was the heater coil, I heard you'd know right away because coolant would be spilling onto your passenger mat inside the car.

Was told to try running for 10 minutes with the radiator cap off to purge the system of any air that might be in it. Haven't tried it yet, but I plan on doing it this weekend.

 

Check the thermostat. Then heater core.

 

FYI air in the system will make it hotter, thus making your heater blow hotter. Bleeding air out will make the engine run at operating temp (which is what you want), but not any hotter.

After a minute or two of running your car without a radiator cap the coolant will start to expand and overflow out onto your floor...I wouldn't do that for 10 minutes. There's a bleed screw on the thermostat housing to get air out.

 

I have no valve there its just a pipe connecting the 2 hoses

 

^ does the temperature of the air change when you try to move the climate control lever? it sounds like the valve control line might have been disconnected. there should be a metal wire extending through the firewall that connects to a valve inside one of those pipes.

hawkze, i've heard that due to the design of the heater core (in/out on the bottom of the core), air can get trapped up inside and not let coolant flow through.

as mentioned, check tstat and also check for a blown head gasket (do a comp check).

 

I had the same problem with my civic. it was no easy fix and it still doesn't give me much heat. I ended up pulling the heater core itself out ( which required removing the dash) and flushed it. It was clogged up with all kinds of gnarly ****. At first I couldn't even get any water to flow through it then I back flushed it an some chunks and whatnot came out. I guess thats my bad for buying a questionable beater.

your best bet would be to remove the intake manifold to get access to the heater core lines on the fire wall and flush the heater core from there. that is if you have already ruled everything else out.

 

i am having the same issue in my 01 civic, booo. coolant level was good, but does anyone have a pic of the valve they are talking about that needs to be open? thanks

 

okay i found the valve and it it works as far as i can tell. when turned to cold it goes in. when turn to hot it moves out. i removed the lower hose and when turned on heat coolant ran constantly when switched to cold it stopped. Any ideas?