Overheating.....sometimes

[Black&BlueHonda]

I have an 2005 civc 5-speed. I had a problem with it overheating...all sources pointed towards the thermostat so that's already been replaced...now when it overheats it only does it while sitting idle in traffic, but it doesn't do it all the time. Had someone else look at it for a seccond opion, it didn't overheat for them at all. I have no idea where to start next...suggestions? Comments?

[Xeryon]

Not to be a complete ass but I copied this from a post I made just a couple days ago as it is almost the exact same troubleshooting steps needed. In this case the previous person had already replaced the thermostat and the temperature sensor. This isn't everything but a handful of 'free' things to check before spending money chasing down your problem.

 

Don't replace the radiator yet. There are other free things to check first.

 

Do not forget to check all of your fuses. It sounds odd but on your car there is more than one fuse associated with the cooling system and they piggy-back on other circuits so they are not marked as cooling system fuses on the block diagrams. After running for a while and the temp starts to climb are both your lower and upper radiator hoses hot? If they are not both hot you may have a clog in your system or the thermostat isn't opening for some reason. You can try running with the thermostat removed to isolate if it is a thermostat actuating issue. Following that you can direct wire your fan temporarily to the battery to make sure that relay hasn't failed. You can disconnect the heater hoses and back-flush the radiator (stick a hose in the top and disconnect the hoses) to make sure it isn't completely fouled up. Last and worst is to replace your water pump.

[Humphries]

air in the cooling system.

 

when engine is cool, open radiator cap and start vehicle with heat on high.

fill with coolant

run car for 15 minutes on an incline

wait until bubbles stop coming out of radiator.

 

put uv dye in the coolant and pinpoint leak.