OK so I just recently bough a 98 accord in good condition. All is running fine and I decide to replace the radiator hoses and water pump and timing belt for maintenance. Well since then the car likes to overheat very easily. If I turn the AC on the over heating doesn't happen. It appears that since changing everything the radiator fans aren't turning on when the car gets hot so thats why turning the AC on seems to help since it turns the radiator fans on. Any suggestions? I tried the coolant bleed screw by the thermostat and only antifreeze came out. I have tried replacing the coolant fan switch on the thermostat housing, replacing the temperature gauge sending unit in the head and replacing the other temperature sensor in the head also. Oil looks perfect, car drives fine. Ideas?

 

Sound like a sticking thermostat, have you replaced that yet? Get a Honda one, it's about $30 or less.

 

OK I forgot to mention yes I did replace the thermostat in an attempt to fix the problem and still over heating. I didn't get a honda one. It appears as thought the upper radiator hose is very hot! and the lower one is luke warm. So perhaps the coolant isn't circulating correctly.

 

Much more likely to be the thermostat's fault vs. the waterpump.

Unplug the fan switch (in the thermostat housing) & jumper the wire with a paperclip. That should make the fans run, just to verify fuses, relays, motors, wiring, etc...

 

Yeah I jumped the plug to the thermo switch yesterday and the fans came on. I eventually got a huge air bubble out of the system by continuously squeezing and releasing the upper radiator hose and after that the lower hose got hot and it seamed to normalize. But on the way home from my folks place where I did the work it seemed too slowly make its way back up to the midway point on the gauge and occasionally hit the 3/4 mark. Could it be that the new thermostat is bad too? I did notice that the original one had a rubber seat built into the valve to seal when it closes and the rubber seat looked worn and the new one is just metal to metal. Just to clarify I am not talking about the O-ring that seals thermostat housing to the engine.

 

Midway point on the gauge (a tad below half, actually) is pretty much standard operating temp for an Accord. If you really want to know if it's overheating, drive it till it warms up, let it idle till the needles starts rising, and shoot the upper hose with a laser temperature gauge, it should read between 170-190.

 

So whats the stock thermostat temperature? Installed a 170 degree one.

 

there is a real good write up in the DIY section,, which will explain + guide you step by step on how to properly diagnose the problem
http://techauto.te.funpic.org/mainrelaydefine.php


click on the troubleshoot tab,, on the left upper side you will see a tab that says overheat,, chk it out

 

Ok problem solved. The car was never over heating. I hit the dash above the temp gauge and it bounced to Hot then I hit it again and it went to normal. SO I pulled the gauge cluster and resoldered the three input socket joints, about 15 pins each. Problem solved. Over 90 miles and the issue is gone.

 

Thanks for posting up the fix, it's crazy how it turned out to be the gauge!