Coolant boiling, engine overheating....

[mazdaspeeeeed]

about a month ago i had a problem with the coolant boiling in the resevoir tank. I replaced the faulty radiator cap with a 16psi cap from Napa and it fixed the boiling/overheating until now.

Just tonight i was driving home and it overheated. i checked the coolant levels and they were a little low so i topped off with some 50/50 and let it cool off for a few hours. drove on it again and it started overheating again... i'm not sure what to do here any ideas?

I had the water pump replaced a few months back with a slightly used
one (30k miles). I am going to call around tomorrow to get a pressure check for any leaks or whatever. lmk if anyone has any ideas....

btw no CELs

[TWISFM]

thermostat gone bad?

[mazdaspeeeeed]

thermostat gone bad?

very possible. I will start with that in the morning and see how things go from there.

any other ideas if that doesnt work?

[TWISFM]

...nah..

[mazdaspeeeeed]

heading to napa now to get a new thermostat...

[MSP2024]

had the same problem, replaced it with a therom and it didnt work, turns out i cracked the rad, it would leak when the car ran but when it was off it would not leak it was kinda weird but i would check to see if you have a crack to

[mazdaspeeeeed]

didnt see any signs of leaking.. i replaced the thermostat and ran the car around for a good 7.8 miles with the ac on and no overheating.

the old thermo had a rattle to it when you shake it and i put it in boiling water and nothing happened.... so yea i believe that was my problem lol.

i am going to continue to monitor the fluid levels to make sure there is no leak.

[blueprotegelx]

Yeah I just replaced my thermostat, water pump, timing belt, rad cap from autozone til my HKS comes in and I drove back to school today and the water temp was very steady between 185-190. Yet I feel like I still smell coolant in the engine bay. I'm thinking it may be from draining the fluid and it's on the frame. I'm going to continue to monitor my levels as well. Did a compression test and all cyl were 180 except #3 which was 190. So I don't think I have a bad headgasket, there was no coolant-oil miture. If levels drop I'm going to order new hoses and corksport radiator.