Rep Power: 0

I've had temperature issues with my Civic for many months now. It started with a trace in the gauge cluster shorting to ground, I replaced that after a while but by the time I got a new gauge, the car was actually overheating. Since then I replaced the coolant, running a lot cooler but still overheating. Then I finally realized that the fan wasn't coming on at all and replaced the radiator fan switch.

Present day - The car runs at a reasonable temperature on a highway trip, and the fan does come on, but the car still does get fairly hot (80% of the way to the red line) when sitting at a red light or two. Any other things I can check?

One other thing - if the car is hot when I park and the fan is running, it shuts off when I turn the car off. Normal?

 
Rep Power: 812

sound like you need a new honda thermostat. old one is either aftermarket or not opening completely. on our cars, yes its normal for the fan to shut off. the engine is small enough and the battery is too weak to keep them on with the engine turned off and its not really necessary. you should wait til the fan stops before turning off the car tho...

 
Rep Power: 0

Gearbox, thanks for the info and the quick reply. I left that part out, I replaced the thermostat a while ago with a cheap-o one, so recently when I replaced the coolant, I used a Stant thermostat, which is supposedly pretty good, so that's only a couple weeks old. If you think it'd be worth it to replace it again with a Honda one I most certainly will. Thanks.

 
Rep Power: 0

you also might have air pockets in the coolant system make sure to get all the air out it could be causing it to over heat, but my guess is the same as gearbox most likely thermostat, i had a similar problem.

 
Rep Power: 812

our older accord would always overheat yet had a new thermostat put in fairly recently. i couldnt figure out the problem so i took the thermostat and tested it in hot water. the thing barely opened. then i tried the test with a new honda one and it opened about 4x as much. installed oem and problems solved. no more overheating and hot engine. the fans hardly even come on anymore when they used to be running nearly non stop and actually burned out one of the fan motors.

 
Rep Power: 0

Thanks again guys. How do I check for air pockets? I drained the coolant and replaced the thermostat myself (not a pro by any means). Either way, I'm pretty sold and will be buying a Honda thermostat. The hard part to swallow for me is that it's just a thermostat - and Stant is in the business of making thermostats. It's like having poor audio quality using Bose headphones and switching back to the ones that came with the ipod. amirite??

 
Rep Power: 812

when you compare the stant with the honda part you will be shocked how disgraceful the stant looks. then when you test them in boiling water you will be even more disgusted lol. just be sure to bleed the air out after youre done. you dont have to drain all the coolant out to swap the tstat, only enough so that you can open the housing without coolant pouring out. be sure to install it the right way. then put everything back, put the coolant back in if its clean or add new, drive the car til its warmed up fully and park somewhere on a hill facing up. you want the front of the car to be higher up so the radiator is the highest point. if not, use jack to raise the car up on flat surface. get a bunch of towels and carefully open the radiator cap. watch for coolant spray. after its off start the car and turn the heat to full hot and fan to max. let the air come to the surface and add coolant to the radiator so it stays full enough to see the bubbles. they should stop in maybe 15 mins. massage the radiator hoses to speed the process. when you stop seeing big bubbles, put the cap back and youre done.

 
Rep Power: 0

Is it likely that 3 weeks after doing the coolant change there are still air pockets in the lines? or should I just go for the whole thermostat change, etc. and not look back?

 
Rep Power: 812

its possible. air does not escape on its own, and our radiator/cooling passages are so tiny. most cars do not even need much if any bleeding of air. but i would for sure put a honda tstat back in.