Rep Power: 0

I'm having issues with my heat, and need some new ideas please.

Recently I noticed that my civic is blowing cold, possible lukewarm air when the heat dial is cranked to full hot. If the engine has been running hard, it will be on the higher end of lukewarm...otherwise, just cold.

I cannot see it being the thermostat, as it was just replaced a few months ago when my water pump was replaced. And, the temp gauge in the instrument panel stays at normal running temp - no fluctuations.

Coolant levels are topped up, and don't fall.

I opened up the rad cap, ran the engine, and got rid of a few air pockets in the system...didn't help.

All hoses get very hot when running - BUT - one that returns from the heater core didn't really warm up at first. I had to work it a little before the temp/pressure seemed to come up - problem??

Anyone have any ideas? Thanks.

- oh, and I'm not really mechanically inclined...so talk slowly and simply

 
Rep Power: 253

hmm u dont overheat? Sounds like a bad heater core or clogged hoses or something

 
Rep Power: 812

okay did you do that first step with the heater on HOT and fan blowing at max? thats the only way to get rid of bubbles in the heater core, which must be done any time coolant is changed (like when doing timing belt/water pump).

otherwise you could have a clogged heater core.

 
Rep Power: 253

good idea..make sure you do what gearbox said. Open the rad cap park on a hill or jack up the front of the car nose up and run the car for some time with your heat on full blast. Make sure that your car is topped off on coolant before you do this. After you do this you may have to add some coolant so dont forget to check your level.

 
Rep Power: 0

Thanks for the responses.

Yes, I did have the dial to FULL HOT and ran the fan at FULL with the cap off. I jacked up the passenger side. Maybe I'll try doing it again right in front and see if that helps.

...hope it's not the heater core. Is that a costly fix?

 
Rep Power: 256

very costly mostley labor cost because the entire dash needs to be disasembled .

 
Rep Power: 0

Awesome...

 
Rep Power: 0

Does your car ever overheat? I know my car was doing this but it also was overheating, found out it was a blown head gasket so I got Honda to replace it, gotta love Honda Care!

 
Rep Power: 0

Nope, never overheats. Temp gauge is steady

 
Rep Power: 269

I had the same issue....never overheated but had horrible heat in the winter. Turned out the headgasket was leaking a TINY TINY bit...

You say the heater hoses get hot (to the core). Are you sure the valve is opening completely? It's between the engine and heater core, next to the firewall....

 
Rep Power: 0

No, I'm not sure...my mechanic did mention it and wiggled it, but wasn't sure what it's movement range was supposed to be...then it detached and he swore for about 10 minutes trying to put it back on...I assume that is what you are talking about...

So, how would I know if it is opening completely?

 
Rep Power: 0

If it is the valve, is that a hard thing to get to to fix? Does it still require all the work of the heater core? Or can it be done without gutting the car?

 
Rep Power: 269

That would be the one...sucks to put the line back on. I believe it has about 90* of movement but am not positive. Have someone in your car with the key on, flip the (temp) **** from hot to cold and vice versa, and see if it moves completely. If it does, then it's probably not your problem. If it were me, I'd just wait 'til winter and worry about it then

BTW, I highly doubt the valve would fail. If anything, the motor/switch would no longer be moving the valve as it's supposed to. Not sure how to fix that, but I'd imagine you'd have to take the dash apart...