Just inherited a 99 Accord LX 2.3 and noticed that the temp gauge does not move past the Cold setting, even after driving around for at least 30 minutes. As soon as I turn on AC the rad fans turn on and cycle on and off very frequently while idling. Can't tell if this is happening while on the freeway, since I can't hear what's going on under the hood. First thing I noticed was that coolant reservoir was empty, I added 50/50 mixture and level remains the same even after running heater for several minutes. No indication that engine is overheating. As soon as AC is shut off the fans shut off also. I've read a couple of posts regarding this problem with a couple of older Honda models but nothing regarding the 99 Accord. Any help with this would be greatly appreciated.

 

With just getting your Accord I would suggest finding out if the fans come on by engine temp. If you let it idle it will take awhile but should come on. You can take the rad. cap off and put a car thermometer in the rad. to see how the temp (the coolant level has to cover the thermometer some) is climbing. Turn the HVAC fan off in the car or it will take even longer to kick the fan on. If the engine temp doesn’t reach the corect temp. replace the thermostat and bleed the cooling system. If it reaches temp. you need to determine if the temp sensor, gauge or wiring is causing the gauge to not to work correctly. Let us know what you find. It would not be a bad idea to flush the cooling system after you have this sorted out.

 

Does the temperature guage move at all? The sender for the gauge is in the side of the head, kinda underneath the distributor. It has a ONE-wire plug. Unplug it & short the wire to ground. Key on, that should make the gauge climb up to HOT. DO NOT let it get all the way to the top, the shop manual warns that you can burn up the gauge.

How old is the thermostat? Much of what you describe can be caused by a bad thermostat (sticking open).

Where are you located? This time of year, I think I would have a difficult time getting the temperature high enough to run the fans. I'd probably have to block the grille with a piece of cardboard. My former 1998 would run the fans when the temperature gauge went a little over 1/2-scale. It wasn't easy to make the temperature go that high.

Follow the LOWER radiator hose over the tranny to the thermostat housing. On the T-stat housing is a fan switch with a 2-wire plug. Unplug that & jumper the wires with a paperclip. Key on, that should make both fans run. DOES IT? If so, then all the fuses & relays & motors are OK.