Urgent cooling system question on 2002 ZTS

[2002-ZTS]

well, about 3 times the expansion cap blew off. i replaced the cap and was fine for a while until it blew off again. i removed the thermostat and replaced the housing and it ran at normal operting temperature until it started overheating again but the cap didnt blow this time but coolant started leaking from the new housing. has anyone had this trouble before? what the hell is going on? take care guys

[Sponsor]

[Weldman0730]

I had a problem with my coolant system before, what had happened is a piece actually broke in the thermostat housing and caused it to slowly leak, it took me forever to figure out what happened. If you look at the housing where the thermostat is, look for any broken plastic, like i said it took me a while to notice it was even broken because the piece was so symetrical and came off cleanly.

Your thermostat could be sticking, I would just replace it, they arn't really that expensive i think i paid like 15 dollars. Also check and make sure none of your hoses are kinked or anything. That fixed my problem, and it only took like 30 minutes.

[GreenEnvy]

how many miles on the car and whens the last time the antifreeze was changed?
i'm going to say your waterpump is shot or the radiator is plugged up.

[2002-ZTS]

water seems to be circulating but i dont discard the water pump being faulty. what bothers me is that i took the thermostat off and it still after a while of driving it started to oveheat. i've changed the coolant everytime it blew off the cap. but this last time i used regular green coolant instead of the motorcraft gold? is that a problem? the car has 50k miles on the clock

[iminhell]

Do the cooling fans come on? (I'm guessing they don't)
I cannot recall what fuses operate them, but your owners manual should have it listed, I believe there is also a few relays involved

(and for the cap to actually blow off the expansion tank takes quite a bit of pressure, a lot more than the 14 or so PSI the system is designed for)

Is the thermostat in correctly?
the dome part should be facing the front of the car, while the longer portion should be facing the rear

It could be low flow from the water pump. If part of the impeller is damaged the pump would move less fluid and that fluid would heat more, and take longer to loose it's heat in the radiator

What coolant mix are you running?
for your location and climate a 70% water and 30% Ethylene Glycol (green antifreeze) would work best. it will offer the highest boiling point at pressure and offer enough anti-corrosion resistance

[Weldman0730]

I would check the fans like iminhell said, If those come on, i would flush out the radiator and replace all the wearable parts, i think i read in a post a while ago someone was having problems with an airbubble in the radiator or something, that woud cause extra pressure, hot gas(air) expands and could cause the excess pressure that blows off the cap.

[GreenEnvy]

doh! my bad, i always forget the damn cooling fans...

[2002-ZTS]

i got my fans wired independently from the car, i did a whole setup with relays and everything, but i am leaning to the air buble problem

the thing is that i dont know if there is a correct way to refill the cooling system, how do you guys do it????

[Peregrine]

Originally Posted by 2002-ZTS

water seems to be circulating but i dont discard the water pump being faulty. what bothers me is that i took the thermostat off and it still after a while of driving it started to oveheat. i've changed the coolant everytime it blew off the cap. but this last time i used regular green coolant instead of the motorcraft gold? is that a problem? the car has 50k miles on the clock

Stick with the Motorcraft gold. It runs about 15-20 degrees cooler than the common green mixtures.

[Weldman0730]

All I have ever done is fill it by mixing up coolant, and then pouring it into the coolant resovoir, once it looks full put the cap back on, allow the car to run for a while until it gets hot, then check the level again, most likely it will go down, so wait till it cools again and add more, until you hit a mark inbetween the "full" and "add more" lines on the resovoir.