If I drive the car for about a mile the gauge climbs up to H. The overflow tank is full and antifreeze comes out the top. I have plenty of heat, I also changed the thermostat. If I sit in the driveway and let it idle it seems ok, but when I rev it up it takes about 20 min. for it to start overheating. I have checked around the head(in the front, cannot see in the back), I cannot see any leaks, and the oil does not look "milky" and I do not see any bubbles in the overflow tank also no oily film on top. I checked the radiator, the top hose is very hot , and the bottom hose is cold. The driver's side of the radiator is hot to the touch, but I can put my hand on the passenger's side. There is no radiator cap on this model, so I cannot see if the coolant is flowing properly.

The fan is coming on, I have tried to bleed out the air in the system, do I do this with the heat on or off (it seems to work better with the heat off)? I do not see any white smoke coming out of the tail pipe.


Thanks in advance for your help.

It is possible your water pump is damaged.

Feel the top and bottom radiator hose to determine if you are getting circulation through the radiator.

Well I changed the radiator and water pump, it's still running hot, but when I open up the cap for the overflow tank the gauge drops back down to half way, and it sucks the antifreeze into the system. Could this be air in the system? I am bleeding it from the bleed screw on the line that goes into the heater core. Is there another bleeder somewhere else that I am missing?

Thanks,
Ted

My friends Sunfire did this, all it was was a bad coolant resevoir tank cap, they are $8, try one of those first.

I just got done with a 96 Sunfire with the same exact symptoms. I replaced the thermostat and waterpump, and thermostat just would not open. Coolant ended up coming out the reservoir cap just like you described. I also bled the system from that heater core line. I finally bought into the airlock theory and drilled a 1/8" hole in the thermostat, about midway between the center and outer edge so any air bubbles would flow through. The thermostat needs water on it to open, hot air won't do it. It has been running fine for a few days. Will post if anything changes.

My friends Sunfire did this, all it was was a bad coolant resevoir tank cap, they are $8, try one of those first.I`d put my money on this idea, and a good quality thermy

Yepp his seal on his cap was deteriorating, thus loosing pressure and allowing coolant to leak out, which in turn overheats the car, cost $8 to fix it lol.

Ok, guys I changed the cap, still does the same thing. Do you think it could be air bound? I replaced the thermostat (the first thing I did), and I am getting plenty of heat. Is there any other bleed screws besides the one on the heater core line?

Thanks,
Ted

you do have the thermy in the proper way. sorry just had to ask .other than that try mrgbfan`s suggestion

Did you replace the thermostat because of this problem, or did it start happening afterwards?

I changed the thermostat because the car was overheating. Now it's not overheating, but it sees to be running a little hotter than usual.

Thanks,
Ted

dude if you got a faulty coolant temp sensor or a wire going to the sensor that is getting shorted out it could give you a false temp reading.

Would that cause the guage to return to 1/2 after I open the tank cap?

Look for a collapsed hose preventing circulation a plugged radiator will also cause this.

Hoses look good, replaced the radiator, water pump, thermostat, and tank cap.

Could you have possibly have put the belt on so the water pump runs backwards. Check the belt diagram.

Nope, that's ok.

1)Close the bleeder hose on the hard metal line. Remove the cap on your coolant overflow tank. Run the car for 25 mins or until at normal operating temp, put the cap back on run for another 5 to vacuum down the system.

2) Get am volt meter and check the voltage to the coolant temp sensor.

Sounds like an air in the system to me. I've had 3 ppl come to me this week with the same issue and # 1 has fixed it for them.

That's what I'm thinking. How long should it take to get the air out of the system? And what is the best way to do this? I am also thinking of taking it some place to have a pressure test done, just to make sure there are no leaks anywhere.

Thanks,
Ted

Sometimes using a floor jack and raising the front helps to get air out. Normally the engine will overheat if the air isn't out of the system. I have used a radiator pressure testor and after filling put on about 10psi to move water into the system.