Rep Power: 0

My wife is now driving my 2002 Civic EX Sedan as a daily driver. She loves her iPod and unfortunately it didn't have an aux port. No big deal, using a DIY from here I put in a new CD player and upgraded the speakers as well. Did this yesterday ...
Get a phone call at work this morning that says whole she appreciatese the new music capabilities, she doesn't have any heat.
The two may be completely unrelated, as I don't remember when I last used the heat.

I checked fuses, checked that I plugged the temp.dial.plug back in (that I disconnected during radio install).
Seems like I get a whiff of antifreeze when I cut the heat on. No wet floorboard. The air coming out of the vents is blowing, but just cold. If you cut the heat and blower off completely and let the car run a little while, and then cut the temp all.the way to hot and cut the blower on, you get a shot of hot air.

Radiator and overflow are full.

I'm at a loss. Feel like I have checked everything I have read about checking. Any other thoughts?

 
Rep Power: 517

Open the hood, locate the heater valve and cable. Watch if they move when the temp is dialed form cold to hot. (They should move to open the water valve when heat is selected.)

If yes, see if both of the heater hoses are hot at the firewall (with the engine all warmed up and running, of course). Valve could be broken or core clogged.

If no, then you need to go under the dash and find the temperature actuator, see if it (and all the linkage) is moving when the temp dial is turned.

Cable end could have popped up off of the water valve too.


There's something to get you started....HTH

 
Rep Power: 307

^^^ Yes, it is on the top edge of the firewall in the engine bay and has a blue sheathed cable leading to it.

 
Rep Power: 0

Update: everything you guys told me checks out. However, the wife said it started running hot on the way home today. I'm thinking thermostat. Looking under the hood, it looks like it lost some coolant, and the coolant was in the battery tray?
Ideas before I tear into it? Thanks.

 
Rep Power: 517

Now check for head gasket leaking.

 
Rep Power: 185

Doesn't sound good. After driving the car, pop the hood, shut the engine off and lift the hood and see if coolant is spraying out the reserve tank. If it is, there's a good chance you're looking at a new HG unfortunately.

 
Rep Power: 0

That's not good. I was really hoping it was a thermostat...do you have to get the coolant testes to see if it has exhaust gas in it?
Any other quick ways to check for a head gasket leak?

 
Rep Power: 185

Deleted due to giving poor advice.

 
Rep Power: 517

Parts store tester with the color changing liquid isn't reliable enough for me.
Compression test won't show anything.
Leak down test using a regulated low pressure tester won't either.

I apply shop air pressure (170+PSI) to each cylinder, then watch the coolant level. Dead-nuts accurate.
I have posted my methods in here many times, search for it.




And all this time you thought it had something to do with the radio install.

 
Rep Power: 0

Thought it was radio install when the only symptom I knew about was it not blowing hot air...soon as I heard about it running hot, that idea was put the window.