Civic EG

1st of all fan wasnt coming on so i jumped the thermo switch to see if the fan was burnt out-fan came on.

Replaced the Thermo switch and thought since i was doing that i might as well do the other temp sensors and a new thermostat(yes the correct way).

Got everything back together, topped off the coolant and started it; everything sounded and looked ok, no leaks, sounds, etc.

Go for a drive and the car starts getting hot on the freeway, so i pull off turn the heat on high hott and its cools to about halfway. Get back home and notice ONLY the top radiator hose is hott and the bottom completely cold!

Just replaced the thermostat too! So my next thought is the water pump.
I squeeze the hose when the car is running and not really any pressure.

So i replace the water pump, fill it back up with coolant, start the car let it run for about 5min. It warms up ALOT faster than ever before so i gt out and check the lower radiator hose-STILL COLD.

Still no leaks, new water pump, thermostat, thermo switch, ect, squeeze hoses and it DOES have pressure but NO flow. Also i dont have a bleed screw by the top radiator hose.


I DONT GET IT.

thermostat just because its new donesnt mean its not bad

tru that, im goin to put another one in and see what happens

was it an OEM thermostat? I've had problems with cheap ones too. The sure test is to put it in a pot of boiling water on the stove and see how much it opens.

aight so i put the new thermostat in boiling water, watch it oped and close so thats not it!!!

what can prevent the thermostat from opening letting the coolant flow through the bottom hose???

I can squeeze the bottom hose and coolant will gush out the top of the radiator, so that kind of rules out the radiator being clogged right?

Maybe an air pocket in front of the thermostat or some debris??

it could indeed be air... did you properly bleed the system? An air pocket can lead to overheating.

hmm not sure is there some sort of sensor for it?

Figured it out!
Went down to Honda, picked up a thermostat and radiator cap.
Came back, flushed it out till drained clear, ran it with out the thermostat
and full flow!
So i put the new Honda parts back in and no overheating!
I guess with out pressure(the water pump being new, and RAD. cap)
the system cant do its job properly. The cap i had on before was only 2months old also, krazy. I dont doubt that the two autozone thermostats werent bad tho lol

OEM > *