Aright here is my prob I have a 1992 Honda civic with a gsr motor and just recently I got kind of worried why my car was always reading cold but anyways I fixed that with a new sending unit. But wile figuring that out i noticed that my top rad hose was hot and my bottom was cold. So I went a felt the radiator and noticed the top half was warm and the bottom cold. So I did some research and thought ill change my thermostat (I tested it about 4 times lol just to make sure it opened and closed and it did every time). So what I don’t know is if maybe I’m not getting circulation when the stat opens or something. Any thought?

also just a noob question i guess but if i start my car with the rad cap off the cooling starts to come up and overflow slowly but it starts to raise and over flow. Is that a sign my pumps working?

I’m so lost and i need this car to go to work and back and nothing is working!!

 

the reason it overflows is because the heat increases the pressure inside the cooling tank.

its basic fluid dynamics. If you heat and pressurize something, it wont stay still. its like applying pressure to a straw and having your drink bubble

with that said, do NOT EVER TAKE OFF THE RAD CAP when the engine is warm. Imagine all that sealed pressure being released BY YOU when you take the cap off. You WILL die.

Finally, it is your thermostat. Replace it. its 10$. A water pump rarely stop spinning since its attached to your timing belt. They usually make noise before failing.

Testing a thermostat outside of your car is pointless anyways. I took mine out, put it in hot/ice water, watched it move around, but as soon as I replaced it, my car was properly cooled


good luck.

 

Start the car with the rad cap off and see if there is circulation!