Trouble with radiator fans

[Zend]

My car recently started heating up real fast, so I popped the hood, and sure enough the fans weren't running. I checked the cooling fan relay, and its not it, I was able to get the fans running simply by shorting it.

I'm guessing its the thermostat on the radiator, my question is:
where is the thermostat located? I cant seem to find it.
Any idea how much a new one would cost and where to find it?

[nutmeg_runner]

I just looked in service manual. They call it a thermosensor and it is located on the lowest part of the radiator next to the lower radiator hose (toward center). Honda part numbers: 37773-PH1-621 030 SENSOR, THERMO (A-90) (DENSO) list price $42.37 or 37773-PH2-004 030 SENSOR, THERMO (A-90) (TEC) same list price. The site where I found the part numbers is selling it for $31.26. You probably should replace the o-ring too. Of course I used my vehicle information(LXi), yours may be different. When looking through the menu choices go for radiator hoses, not radiator. The service manual does describe a coolant temperature switch test. Also in the LXi only there is a second coolant temp. switch "B" which operates the condenser fan for a maximum of 15 minutes after turning off the ignition switch with coolant temperature in excess of 226 degrees F. The A-90 in the part description above refers to the A switch which activates the fan at coolant temperature above 90 degrees Celcius. Hope that helps.

[Mac]

You might want to check that your thermostat is working. Just follow the radiator hose to where it goes behind the distributor cap. The thermostat is in that housing.

[Luis 89LXi]

My car was doing same thing, one day fan just stop doing its job, i checked wiring, thermosensor and Fan relay, everything fine, the problem was the Fan Control Unit located below passanger seat, have all tree diodes burned.

I just replaced whit Zener Diondes and its working OK.

Luis

[Slavic]

I'm guessing its the thermostat on the radiator I guessed that too the other day. My dad asked me 3 times if there's a fuse and If I checked the fuse. But noooo, I was sure it was the temp sensor.

Just check the 15 amp cooling fan fuse in the black box by the battery before You mess with the hard to reach temp sensor. It may save You the trouble.

The sensor is on the low part of the radiator next to the lower radiator hose and the drain screw. It's 22.49 at AutoZone. (I was that sure it was the temp sensor I sourced it before testing.) They refer to it as temperature switch. If You find it for $13 elsewhere You may be quoted for the wrong part as I was the last time I changed it so try to bring the old one with You so You can compare and save Yourself a trip.

You'll know it's bad if You short the contacts of the wire that plugs into it with the car running and the fan turns on. Otherwise check the fan. Quick fix is to leave it shorted until You buy the replacement sensor.

[Zend]

lol, the 15 amp fuse was the first thing i actually checked, then from there i went to the relay, shorted it and it worked fine, swapped the relay with a known working one, didnt work. So I'm pretty sure its the sensor.
I'm just gonna wire up a light switch to short it when i drive my car.

[mouchyn]

lol, the 15 amp fuse was the first thing i actually checked, then from there i went to the relay, shorted it and it worked fine, swapped the relay with a known working one, didnt work. So I'm pretty sure its the sensor.
I'm just gonna wire up a light switch to short it when i drive my car.

spend the $15 and fix it right. ghetto rigging is so stupid. you got no respect for the car or the quality of your own work.

[Zend]

It's only a temporary fix till i can do it right...and the $15 is supposing thats whats wrong.

[Mac]

You can check both the thermostat and temp switch with a pot of water. Remove both and put into pot of water. Wait for it to boil and see if the thermostat opens up. If you have a meter put it on the temp switch and when it boils see if it closes.

[Zend]

Ok, thanks for the tip.

[ISingBass]

Hey, all.
I am having the same problem with my car right now. Maybe I'm just really dense, but I cannot find the fan relay to check it. I've looked and looked, and don't even see a location in the factory manual. Could someone please tell me where it is?

[ISingBass]

:uh: Oops! I think I found the answer in Cooling fans not turning on, Missing plug on temp switch. (http://www.3geez.com/showthread.php?t=38295)
I'll go from there. Thanks, anyway.

[mouchyn]

the fan relay is in the underhood fuse box, by the way

[ISingBass]

Thanks, Mouch. It turned out to be the thermosensor.
There's not enough clearance from the frame to acces the sensor, so I just ran a ground to the other side of the relay in the fuse box to bypass the sensor. That will keep the engine cool until I am ready to pull the radiator. :)

[mouchyn]

you shouldn't have to pull the radiator to get to that sensor. I didn't.

[b8er]

yes its definatly the thermal sensor, i just had the same problem , bought a new sensor and it fixed the problem, you dont have to pull the rad, thats way to much work , i beleve its a 21 or 22 mm wrench, its a 5 min job

[Versanick]

My passenger side fan had a broken or shorted wire somewhere between it and the fusebox. So I just put it on a switch and keep it near my shifter. I turn it off when I turn the car off. I turn it on when the temp gets close to boiling (with temp gague). For all practical purposes, I leave it on. The car starts to get real hot when the driver's side fan doesn't come on for a long time. Instead of replacing anything at all, I think I'm just going to put that on a switch as well. An engine should probably run at more like 190 deg instead of 210-230 range.

I suppose your iron blocks may be different, in terms of the a20 instead of b20.. I also assume that the aluminum will warp more easily. So I'm just being careful.

But if all else fails, put it on a switch. I already have my starter on a switch (yep, I have to turn it off when the car starts after turning it on to crank the starter) and my other fan. Time for a third.

Just keep the engine cool. If both fans are running while the car's running at all times, you won't overheat.

[Versanick]

For the driver's side fan, the blue wire with the brown dots on it... cut it, run a wire to a switch, and the other wire to the + side of the battery (or some other hot source). Turn it on whenever your car's on. Or you can wire it to be on with ignition on. That doesn't matter.

The thermostat is right below your distributor. The huge hose that comes from the top half of your radiator and goes right to your engine below yoru distributor... where tha those leads is where your thermostat is. There are only two 10mm bolts on. Unbolt them. Get ready for a mess. The thermostat pops right out.

Buy a thermostat at any auto parts store for an 86-89 accord. get a 180 degree thermostat instead of the factory-installed 195 degree one. and the gasket that goes with it (won't cost more than $10 total, or shouldn't). Put the gasket on the thermostat (you can figure out how really easy, even if you've NEVER worked on a car). ... stuff the thermostat in right from where it popped out (very simple, and you really can't mess it up... just make sure you orient it the way that it was oriented, there's a little pin and some bumps that go on the top.. and the correct end facing out.

then put the fitting back on with the 10mm bolts and put the hoses back on. new thermostat. and with the fan on a switch and a good thermostat, your car CAN'T overheat. no matter what everyone else tells you about a thermosensor.

good luck.