Temp gauge runs hot but car makes no heat...... HELP
 

I have a stock 97 Civic DX coupe. A few days ago while driving I noticed the temp gauge was running hot, sometimes real hot, i turned on the heat to try and get it to go down but all it was blowing was cold air. I figured my theromstat was going bad so I replaced that and it did nothing. So then I spent 7 ****ing hours tearing the dash out to replace the heater core and that also did nothing to fix the problem, it made it worse. Im stumped on what it could be, maybe a clogged radiator?? Any help would be awesome, im losing my patience fast and I have a real big hammer close by.

Re: Temp gauge runs hot but car makes no heat...... HELP
 

Stock Y7 and no CEL's also.

Re: Temp gauge runs hot but car makes no heat...... HELP
 

the only time that happened to me was there was no coolant in the radiator. The heater gets it heat from the hot coolant. So either you have no coolant, or you have a clog somewhere.

Re: Temp gauge runs hot but car makes no heat...... HELP
 

Its full of coolant. Im thinking a clog also. I might let it run for a while tommorow and check the hoses to see if any are cold. ran out of daylight today.

Re: Temp gauge runs hot but car makes no heat...... HELP
 

It could be the heater control valve for the heat (or clogged heater core lines). It is what the temp. slider is attached to. This is between the engine and the heater core (under the hood). This might be the problem for no heat, but does not answer why the car is overheating. It could have been low on coolant, and boiling out. This could be caused by a faulty rad. cap, not keeping the pressure up. Also, since you changed the thermostat, make sure the coolant is bled properly, open the reliefe valve (somewhere around the thermostat) and run the car till the rad. fan turns on. Coolant will pour out, close it when there is no more bubbles coming out. If the car overheats while sitting, it could be a faulty fan switch.

Quickest and cheapest way first, change the cap and re-bleed the coolant system.

Re: Temp gauge runs hot but car makes no heat...... HELP
 

this isnt environmental friendly, but you could put a hose in the radiator and remove hoses and see if water is coming out. You need to remove the t-stat though.

Re: Temp gauge runs hot but car makes no heat...... HELP
 

well if the temp gauge is reading hot then there is coolant in the system. cause if there was a leak, and it was empty and overheating, the coolant guage would probably read normal since there is no coolant to heat up the temp sender.

Re: Temp gauge runs hot but car makes no heat...... HELP
 

Temp slider seems to be working fine, checked it thoroughly on both ends. I'll take out the heater control valve tommorow as well to make sure its not clogged. Rad cap is new. Going to bleed the system tommorow also. Hopefully it works. Ill keep it updated.

Re: Temp gauge runs hot but car makes no heat...... HELP
 

The problem was the brand new thermostat was bad. I popped it out the next day and let it idle to to see if any hoses were cold, they were all warm so i knew it was bad. All this work for a $17 piece of shit defective thermostat.

Re: Temp gauge runs hot but car makes no heat...... HELP
 

Dare I mention.. your new thermostat was probably okay. The problem was likely that you installed it backwards! :cry:

Re: Temp gauge runs hot but car makes no heat...... HELP
 

Ancient thread locked.