odd overheating problem...please help

[rwoody76]

ok - i have a 92 accord that overheats if i drive it for more than 20 miles.............i have to keep the thermostat on hot...if not it overheats....most of the time i keep it on defroster mode as well but this isnt cool in the spring / summer........its ok now while its cold

it especially overheats after driving 20 an dup miles when i am stopped..........either in a parking spot or a light...i really have to turn the defroster on high heat then.............

the odd part is i have replaced everything i can think of to fix it and dont know where to go next.........i replaced the thermostat, radiator, any bad hoses, and flushed the cooling system and put in new coolant.the water pump was replaced in the last year or so prior to me purchasing...........

any ideas / suggestions would greatly be appreciated..........would like to get it fixed before the warmer weather comes around again

[Ehscrewdude]

Do you still have the heat shield on your header? that could be your problem as I've heard of that from others...

[jeffcoslacker]

Possible your primary fan isn't working. Sounds like you aren't moving any air through the radiator when the car is stopped, and you are making up for it by blowing heat out through the heater core. Does the temp come down when you start moving again? If so, that's what you got. Causes would be sender switch bad, relay bad, fan motor burned out, wiring break.

Good luck with it.

[AccordCodger]

Fan relays seem to be a common Accord problem. There are a pair of them, probably mounted in clips against the inside of the right fender (next to the cruise vacuum actuator). I dount they'd both go bad at the same time & they are the same type. So if you're comfortable trying it, you could switch the 2 relays temporarily, DON'T run the A/C, drive your car around and see if it fixes the problem. If it does, it's the relay. If it doesn't, try the other things jeffcoslacker suggested.

[rwoody76]

thanks for all the ideas.........when i was checking out the wiring diagrams the fan switch kept coming back to me.........the fan does not kick on when the temp is high unless you turn on the blower for the defroster or a/c........
and yes it cools down when starting again from a stop.........that was another reason i kept going bck to the fans cause when i am moving the air is circulating...............
the fan always runs once the car is off for 2-5 minutes, but i have heard other accords in similar years doing so as well............
i will definitely try switching out the relays to see if that changes again.......
thanks again and if that doesnt work i will let you all know to see what other ideas you have.........my other thought was i got the wrong or a bad thermostat...................

[rwoody76]

and also......both fans work when forced to with the defroster.........so i know the actual fan isnt bad.............

[jeffcoslacker]

So when you run with the defrost on, does the temp stay normal, or no?

If so, and you said you verified that both fans will run, then try connecting the leads going to the fan temp sensor (I don't know where it is on yours) together with a piece of wire and see if the primary fan comes on then. If so, the rest of the system should be good, but the sensor is malfunctioning. I'm assuming a two wire sensor. If one wire, then you just ground it to the motor to make the fan come on.

[AccordCodger]

If both fans run (at all) then the relays are fine. (And by the way - my bad - they are on the inside of the LEFT fender)

[rwoody76]

thanks again............
yes the temp stays normal with defroster on high heat.............i will have to check out the sensor this weekend..........if i remember from the wiring diag there are two sensors for the fans........one to kick on at a certain temp and then other to kick on at a higher temp.............anyone one the best way to test which one it is??????

[jeffcoslacker]

Originally Posted by rwoody76

thanks again............
yes the temp stays normal with defroster on high heat.............i will have to check out the sensor this weekend..........if i remember from the wiring diag there are two sensors for the fans........one to kick on at a certain temp and then other to kick on at a higher temp.............anyone one the best way to test which one it is??????

If I remember, there are two near the thermostat, one is probably for the gauge, the other for fan operation. (just guessing here, but that's typical) If one has one wire, ground it to the engine with the ignition on, and see if the temp gauge swings over to hot. If so, that's the gauge sender. The other has a couple of wires, shunting them together SHOULD make the fan come on. I guess if it does, for the purposes of testing you could leave them like that, and drive it to see if the problem is gone with the primary fan running. Not sure about the higher temp sensor. I know some would turn on the secondary fan under extreme temp situations, or change fan speed to a higher level, but I am not certain on yours if or how this works.

I'll leave that tot the codger.

[jeffcoslacker]

If you connect the leads together and the fan runs, make sure you protect the connection from touching anything. If it grounds out, you may have bigger problems. Tape it up good before driving it this way.