I have searched and read a lot of threads here on overheating but there are so many that I cant seem to narrow down what my problem is. My 93 Accord gets hot while idling but the fan that is supposed to cool things off only cuts on after I cut the car off. Then the fan runs for some time. Temp guage okay while car moving but rises quickly when idling at lights. Thermostat functioning because top hose very hot with coolant returning to radiator and bottom hose warm-hot with coolant going back to engine.

I think one of the coolant temerature switches I read about in other threads is the problem, but the car has different switches that sound the same in my Haynes Manual. Based on the symptoms, does this sound like it is being caused by the radiator fan switch, or something else? Thanks for any thoughts.

 

This is almost certainly Thermoswitch A failure. Since it never closes, the radiator fan can't come on unless you turn on AC. You can confirm by putting a jumper wire across the thermoswitch connector. W/ jumper in place the fan should run all the time w/ the ignition ON. New Thermoswitch A should fix your problem.

Fan running w/ car OFF is correct. There is a second Thermoswitch B which closes at 226F and will cause the radiator fan to run w/ igntion OFF. This is shutdown cooling to protect against heat soaking from a hot, recently shutdown engine. A timer limits fan run time to about 15 minutes.

Thermoswitch A is on the thermostat housing.

good luck

 

Thank you KatyHonda. That's good info. I'm going to drop by Honda and pick up that switch today. If you don't mind a couple of followup questions: the Haynes manual makes it sound like that switch can be popped out and in with no tools. Is that correct? If not, do I need to turn the large nut at all or just twist the switch itself to remove it?

 

LOL, you must have been reading my thread cause i had the same problem. i replaced the thermoswitch and it is better now, but you'll also have to bleed the radiator. in my thread, i posted the technique to use. and my car is running great now. fan turns on when car is on too!!!!!!

 

Remove the connector and use a deep socket to remove if possible. Next would be an open or closed end wrench of correct size?. It is tight because of thread sealant, which should be on your new thermoswitch.

Make sure you get a thermoswitch that matches the base color of your old thermoswitch (old will be faded). I think it's purple. I was sent the wrong switch and had to return.

good luck

 

I think I got the wrong part! Despite me telling the parts guy that the nut did not look right on the part and saying "radiator fan switch" over and over, I left there with a part that has a skinny nut on it and now that I look in my Haynes, It sure looks like he sold me "Switch D" or the "coolant temperature sensor for the ECM." It has a white connector. The picture in Haynes clearly shows that "Switch A" (the one I need) has a farily wide nut. I am sorry I did not have the Haynes with me. It is so frustrating. Of course for one of the tech's to look under the hood and identify the part would require that I check the car in and pay them $69 minimum labor charge. GRRRR!

scrubachu, your post is very timely. Do you happen to still have that Honda OEM part number for that switch? What I purchased is "37870-PK2-005 Sensor Assy." Without a part number, I don't think I have a chance of getting the right part, especially since I refuse to give away $69 for a "diagnosis." If you or someone has that part number please post it. Thanks.


Modified by brakedrum at 11:30 PM 10/15/2004

 

See following link. I don't think the number in this listing is the official Honda part no.

http://www.hondaautomotivepart...ENSOR

You need the A-93 part. This is for 93 deg. C switching temp (~199F).

good luck

 

Thank you KatyHonda. Now I'm getting somewhere. Based on your link, I looked up the following picture on another site. Is this the part and should I say A-93 Thermoswitch to the parts people at Honda or some other name? This is a big help. Thank you again.

http://img.eautopartscatalog.c...C.JPG

 

It looks correct to me. It should match the part removed.

good luck