Weird Overheating.

[92Inspire]

Ok fellas (and ladies), im a 4+ year technician and i know cb7s like the back of my hand. I have a 91 lx 2 door manual. here is the problem. first only one fan works and only works when it shouldnt, the car will peg out hot and the fan will never come on but as soon as i turn the car off it will kick on. (ignore the other fan its dead the motor is done). the fan that works is the cooling fan on the left (if your facing the front of the car) relay is good, im going to be swaping the switch on the thermostat today because i checked continuity and it had none so i think thats my problem there. but heres the fun part. ive pressure checked it 4 times for over 15 min at a time and no external leaks. no water from the weep hole and the water pump is new. ive bled the system many times to expel all the air. did a head check 3 times no hydrocarbons have been detected but still it over heats even if i jump the fan and it constatly runs.if i put a spill free funnel on and fill it with coolant or water and let the car run it constatly has air bubbles but it wont overheat that way with the fan off. in conlusion what i get from this is that some how im getting massive amounts of air in the cooling system and there is no head leak or external leak, im going to replace the thermostat, radiator cap and pretty much all the coolant hoses within the week, also going to see maybe if the IAC or Fast idle valve or throttle body have anything to do with the air considering they all have coolant lines running to them. if any one has come across this or has a GOOD idea about what this might be please reply or send me a PM. p.s. please read this carefully befor u respond with something i have already explained. thanks and i hope u guys can help.

[BoSNiAN Honda]

sounds like the switch.. my car does that 2... its doesnt overheat tho lol sounds like a bad switch or a bad timing belt

try changing all those first then get into all the other stuff.. first fix 1 problem then the next should solve itself or you should get a better mind on it

[cloudasc]

Sounds like a thermostat issue, its probably stuck partway open, also if the fan isn't coming on then your fanswitch on the thermostat housting needs to be replaced. There is a different fanswitch that turns on the fan when the car is off. If you have a/c turn it on, it should also turn on the radiator fan. If after you top off your coolant, drive a little bit, and let it cool overnight, if the thermostat is closed, you should hear/feel suction as you remove the radiator cap. If its stuck open, no hiss/suction. If the thermostat is stuck closed your car will overheat because water wont be able to circulate out of the engine to the radiator.

[pz3rd]

It's the thermostat switch- common issue that occurs It's happened to many of my friends civics and accords. I could be wrong but the switch is supposed to turn the fan on as soon as the car goes above operating temp. not after you shut the car off.

[pz3rd]

I think the switch is located on the thermostat housing. since your going to change the thermostat, change the switch as well.

[92Inspire]

ok i found the problem last night, i changed the switch on the thermostat housing just incase that was the problem and it still didnt do ne thing to help i still had the same problem (who ever said the ac fan should come on, if you didnt read my thread i said that only one fan works the other is DEAD the motor is done) anywho the problem was the fan timer relay, for those who dont know about it it is located under the dash right next to the main relay, i opened it up and low and behold a resistor had poped (sounds familiar-main relay) well it was only letting the fan come on after the car was off, i have no idea why it would even let it come on at all see as the resistor was poped. but i saldered a new one on and low and behold the fan works, with the ac on and when the car gets hot. but im still having a problem with the cooling system itself. i do agree that the thermostat is bad or going bad what it seems like is its sticking and opening when ever it wants causing a restriction. the radiator cap is also going bad, i found that out last night as well it will periodically let coolant through and dump into the resivor. i also have a BULK heater hose in the back that i had to use a hose coil on and over the period of a month or so the hose has gotten week and is now bent causing a restriction. im going to fix all of this and hopefully it will fix the problem. thanks for the replys and ill try to get some pix of the FAN TIMER RELAY for those who dont know about it. thanks for the help guys and ill keep you posted on the progress.

[cloudasc]

If you turn your air conditioner switch on inside the car, both fans should turn on is what I specified (or one in your case if the motor is dead on the condensor fan, the driver side one). Radiator caps are meant to bleed to the resevoir once they reach a certain pressure whether its coolant or air. Once the coolant cools, the pressure is reduced creating a vacuum sucking fluid out of the resevoir and into the radiator. If the rubber on the bottom of the cap looks cracked, or when in doubt just replace it. A new thermostat and radiator cap should be less then $25.