about 5 weeks ago I Had my first problem with my car overheating.. I didnt have another problem with it until about 2 weeks ago. then last weekend it happened again, and then twice in the past two days.. SOOO now, im really starting to get worried.

I need help diagnosing the problem, any experience or suggestions are welcome. here are the symtoms: (if it sounds like im repeating myself, i probably am)

-car only overheats when sitting still
-fans DO NOT come on when it overheats
-fans DO come on with air conditioning
-car cools down when fans come on
-the car will NOT overheat when the hood is popped, only when the hood is closed

the first things that come to mind, are- thermostat malfunctioning, blown headgasket, wiring to the fans.. although I dont really know where to start looking for stuff if it comes to wiring wiring scares me..

I dont think its a blown headgasket, i just did a compression test yesterday, 200,190,195,190 so that is fine, but I did see some whitesmoke/smell coolant when I was backing out of my driveway today with the AC on full blast.(wasnt condensation i had been driving all dey before that, dont know if having the AC on full blast could cause sumthin).. but that is the only time ive seen/smelt white smoke or burning coolant.. also there is no water in my oil or any of the other headgasket symtoms so i dont think its that..

Im pretty sure it has something to do with the fans, but I dont really know where to start looking to get to the root of the problem.. any help is greatly appreciated, TIA.

chris

 

wish i can help, but i dunno what to look for. Check the thermostat (I dunno how to tell if its gone bad) and pull the fan to look over the wires and everything. Actually check your fuses first... you never know.

 

check your fans first. I wouldnt worry about the smoke...could have been the atmosphere humidity or condensation.

 

check the cooling fan fuses first. next check the cooling fan relays.then check the coolant temperature sensor. probably will be a fuse. good luck

 

you can tell if a thermostat is bad by putting it in a pot of water and bringing it to a boil on a stove. if it opens, it should be good. sounds more like an electrical prob. but i'm no pro. Wish i could help, good luck Direp.

 

When you are standing still and your fans aren't on then you have no air flowing through your radiator to cool your coolant (obviously). I would check the thermostat, it could possibly make it act up, however the main point of your thermostat is to prevent overCOOLING not overheating! but first I would just hardwire the fans to a 12v ignition source, so they are on all the time and see how she likes that, or you can run your fans to a switch, just don't forget to turn them on/off! You can also try redline water wetter, which can drop coolant temperatures up to 20 degrees. Also make sure your radiator cap is good, if it doesn't seal properly then your cooling system won't be under pressure which will lower the boiling point of your coolant, possibly causing it to boil and overheat! Of course also make sure you have a enough coolant! I hope some of this rambling on helps you, good luck.

 

Sounds like a bad thermoswitch...thermoswitch is on the back of the thermostat housing.

 

That crossed my mind too but I think that would trigger a CEL!

 

I rewired my fan because of this same problem...now the fan is controlled by me...

I usually leave it running all the time though...

 

no, actually it wouldn't.

 

check
-fuses
-coolant level
-hoses
-hose clamps
-air in system

 

probably something to do with the thermostat. although, at the very least i'd do a coolant flush and refill. it can't hurt.

Tom

 

Just take off the themostat, so coolant runs through fully, this will cool things a bit.

 

Never ever take the thermostat off. Find out the problem and fix it. Are you in the dallas area? I work for park place lexus in plano I can look at the car for you.
jason phan

 

See any leaks on the radiator?

 

Ok.. had same problem recently:

1) Since when you turn on the A/C, the radiator fan comes on, that means that your fan works.. your fuse is ok. Does your condensor fan come on too?
2) If you are overheating with the fans not coming on, AND your fans turn on when you turn on the A/C, then the problem is MOST DEFINITELY either your
Thermosensor (also known as auxilary fan switch), or the relay. Check the relay
by grounding the positive wire that is hooked to the thermosensor/auxilary switch.
This should cause the fan to start if the relay works. At this point, if the relay is good, then the thermosensor/aux fan switch is bad. ($25-35 bucks OEM)

 

I had the same problem, spent a lot of time on it too....In the end it was a fuse

 

thanks for the help everyone.. I havent started working on it yet, but now I have a few good ideas of things to look for tomorow..

I want to know more about this thermoswitch, or auxilary fan sensor.. I think this may be it because of 1 symtom i forgot to mention. --- when I first installed my turbo, I remember the fans ALWAYS coming on, everytime I would pull in the garage the fans would come on and start blasting air.. NOW, it doesnt do that anymore.. so im thinking somewhere along the way, something went bad..


[Modified by DIRep972, 6:30 AM 5/17/2002]

 

I agree with Willis about the thermoswitch. If you had a bad relay, I would think your fans wouldn't come on at all. I doubt it's your themostat because you would still overheat if your car was running. The reason why is because when a thermostat goes bad it sticks in the closed position, so that coolant won't flow. Thus if it was bad, you'd still be overheating when driving.

 

your car just missed me that's all..... LOL

try to flush the rad fluid first man...

 

Im goning over to your place today so we can figure it out..

art

 

I'm quite sure it will be the fan switch. fans work with ac, and they're not running when the car gets hot. has nothing to do with the thermostat. need a new switch. if the thermostat were sticking to make it overheat, the fans would still come on, just wouldn't cool much.

 

you car uses an electrical thing next to the termostat housing( dont know the translation) try exchanging that with a friends car, in all hondas they are the same, dosent matter if its vtech or not.

This temperature activated swich is the one that activates the fans when the car reaches its working temperature, but gets overided when you turn the air conditioning on, that coud be the problem.

 

alright, I found the fan switch but how do I test to see if it works? I have a haynes manual but im confused on what to do to test it.

One more thing I noticed. When my car warmed up and reached regular operating temperature, I would let it sit for awhile, and I would hear the fans begin to wind up but they fail to come on.. at one point when I was trying to test the fan switch they tried to come on for 3-4 seconeds, but then they turned off when I took the test meter away from the sensor. (dont know if its related to the test meter)

art? eheh sleep in a lil?

also, I just did another compression test, my motor is fine.. but on # 4 cylinder it was kinda odd.. the pressure built up to about 190psi, fell down to 180, then climbed again to 190. is this normal for a compression test? ive never seen it behave like that.


[Modified by DIRep972, 12:30 AM 5/18/2002]

 

That is EXACTLY what mine was doing. I replaced the thermoswitch and that was it...end of problem.