The other night I passed a car overheating (Subaru) and checked my temp gauge and saw my needle was gradually climbing towards the half mark. This is not normal for my 96 Honda Accord. No lights coming on, so I blasted the heater and needle immediately returned to it’s normal position. Filled the coolant, it was low, but the problem remains if the heater isn’t turned on to at least 3. This doesn’t seem extreme enough to be the thermostat. Could my fan be out?
Your fan may have stopped working. The next time this happens, slow your heater fan to 0 or 1 as you approach home. Let the engine get near half-way; drive around the block if you need to. Stop the car at home and open the hood. is the fan running? If not, have it checked. The fan should run after the engine is shut off, although you could see if ti runs while the engine idles. It’s just easier to hear the fan if the engine is shut off.
In addition to checking the fan, your radiator may have reached the point of being less effective due to age and deposits accumulating in it. By turning the heater on, you have essentially just increased the capacity of the cooling system.
Would a radiator flush help? I am AT LEAST the fourth owner of this car and have very spotty maintenance/repair records. I never hear the fan running after I shut the engine off and all my drives are 25mi. or more. I live waaaaay out from civilization. I do plan to do the test suggested by the first reply. I have shut the heater off since filling the coolant (radiator and reservoir) to see how long it takes to make the needle rise and it takes about the same amount of time.
It could be a sticky thermostat, especially if original.
I changed the thermostat every 4 years on my 88 Accord.
Yes. Flush and fill with the fluid recommended in the owner’s manual. Some Hondas need Honda fluid. If you (or a previous owner) have been using the wrong fluid, budget for a new radiator.
It would help to know where you live and what the weather is like - i.e. in terms of ambient air temps. If your temp gauge is climbing as you drive then I’d not suspect the fan first, especially if you live a cold climate. I would suspect the thermostat.
But if your coolant level was low then you do have a leak. You need to find that.
And you’re asking about flushing the radiator. So I’m thinking you should just take for a full cooling system service - flush, pressure test, fan check, new thermostat & radiator cap.