Temp raises after long idle times (not normal)

[VRDrvr]

Car: 1990 accord
Problem: I recently changed my radiator approximately 3-4 months ago and have had no problems thus far. Well the other night I was sitting in my car just hanging out with a girl and looked down at the speedo and saw my temp gauge was about 3/4 of the way up ( a little more than normal) then I quickly turned on the a/c which turned on the fans and the temp gauge went down. I know the fans are still turning on and still functioning but when it heats up I don't feel them kick on.

Radiator fluid is full and clean, but another thing is when I shut off the car if/once the problem starts and I turn it on to the temp gauge is at like 1/4 so could it be the temp sending unit?

I have no problem with overheating during driving or anything like that but if I am sitting in at idle or at a stop for 10-15 minutes it starts to overheat...I am thinking thermostat but typically wouldn't it be all the time for it would be stuck open/shut/partially?

TIA

edit: changed my thermostat problem still persistant could it be temp sending unit or something?

[91AccordLX]

ive heard that if you dont bleed the coolant system right there will be air bubbles in hte system, and that causes overheatoing sometimes.....i believe there is a trouble code for the temperature sending unit...check your ECU codes and see what you throw..btw hte temperature sending unit is right on the thermostat housing, its a green plug..i think....

[91AccordLX]

hey man did you fix your overheating problem while idle? my car is doing it now..and i just changed my thermostat as well..

[accordme93]

Sounds like the fan relay is shot. Same thing happened to me. I'd be sittin in a drivethru and the temp guage would shoot up quick.

Think its a dealer only part which sucks.

[ckyskater733]

is it the water pump? i think thats what its called.....

[91AccordLX]

well hey, i put my old radiator cap on just a sec ago....and i got all the bubbles out of the system...but i havent drove it yet, i let it idle for like 15 minutes and it didnt get hot....but i dont think my fan relays are bad, because BOTH my fans kicked on when the car got to optimal running temperature...but i was talking to a buddy of mine, and he asked me where i got the new thermostat at, and i said o'reillys, and he said never get a thermo from them, he gets all his parts from them except thermostats, he goes to autozone for thermostats. but both my upper and lower radiator hoses get hot, so i think the thermo is working also...because if it wasnt, wouldnt the lower hose not get hot? i believe accordztech said that somewhere on this forum...

[Backfire32]

i had the same problem a while back. it turned out to be the thermostat. i changed it and all was well.

[91AccordLX]

well i bought a thermostat from auto zone, and no overheating yet!! but my lower hose is still getting really swollen right where it connects to ther thermostat housing...

[shimoto]

bringing this back to life

well this started happening to me when i took the car out tonight. i stopped at a light, and once it hit green (no more then 2 minutes) i noticed that my temperature was at 3/4 and still rising. i thought to myself, shit i'm going to overheat... but played it cool, and drove on. it went back to normal temperature. when i stopped quick at my friend's house, it started to rise again while i was in reverse... is it my thermostat? or could it be anything else?

[shimoto]

bump, need help

[mrhonda]

First check and make sure that BOTH fans are comming on and cycling normally.

[jhondayaaj]

bringing this back to life

well this started happening to me when i took the car out tonight. i stopped at a light, and once it hit green (no more then 2 minutes) i noticed that my temperature was at 3/4 and still rising. i thought to myself, shit i'm going to overheat... but played it cool, and drove on. it went back to normal temperature. when i stopped quick at my friend's house, it started to rise again while i was in reverse... is it my thermostat? or could it be anything else?

you know, there is a switch called thermoswitch. if that is bad, it will cause your cooling fans not to come on when it is suppose to.

[accordztech]

humm is both hoses hot? if they are then its not ur thermo at all.

when the fan kicks in does it go down?

you may not have efficient cooling, there may be crap on the radiator fins that air cant flow through smoothly, or your fan shroud for the radiator fans is ghettorigged or not on the radiator, killing usuable cooling.

does it do with the AC running?

is the fans running fast or slow? my uncle had a issue where the fan was just operating too slow...lol it was weird and turned out to be both fans just going bye bye.

there are 3 control units for the cooling system; coolant temp sensor, condencer fan sensor and something else. one of those can be out of wack, those range from 20-60 a piece or a good trip to the junk yard.

[VRDrvr]

bringing this back to life

well this started happening to me when i took the car out tonight. i stopped at a light, and once it hit green (no more then 2 minutes) i noticed that my temperature was at 3/4 and still rising. i thought to myself, shit i'm going to overheat... but played it cool, and drove on. it went back to normal temperature. when i stopped quick at my friend's house, it started to rise again while i was in reverse... is it my thermostat? or could it be anything else?

Well the reason mine went was because I didn't tighten all the clamps and connections tightly and this caused fluid to leak and thus no fluid in my radiator. I would check all connections to hoses, check hoses and also that when you turn on your a/c both fans come on.

[KillerCam282]

Here are some causes of malfunctioning fans.

Blown Relay or a Bad connection( No CEL given, fans just don't turn on)

Bad Thermoswitch
3 switches ( 1 on the rear thermostat housing, on the cylinder head and one on the from thermostat housing) Usually gives a CEL

Bad thermostat
Open the radiator with the car warmed up (be careful, don't force it and wear some clothes you dont care about) , if it opens up easily then a thermostat is bad.

Bad fan motors
Run the fan to the battery to test if its running properly.