Overheating & Anti-freeze boiling, Please Help

1989 Thunderbird, Base 3.8 V6

OK, yesterday I noticed my temp. gauge climbing a little higher than it should. I also noticed my inside vents were pushing out cold air, even though I had the heater on hot. My mechanic said the thermostat may be defective. I figured I would pick up a thermostat after doing a little research on which ones are good, and which one are just OK. So for now I removed the thermostat and all seemed fine, until a few hours ago. Basically I have the exact symptoms as before. Temp. gauge is climbing as I drive, and lowers a little bit if I stop at a light or stop sign. And with no thermostat in the car, I'm still getting no heat when I put the heater to hot. When I first removed the thermostat yesterday, I was getting heat inside the car, and the temp. gauge barely moved out of the blue area on the bottom.

I was thinking there may be pockets of air in the cooling system, so I was going to try to release that little bolt to bleed the cooling system. Thats when I noticed the antifreeze in the reserve tank boiling.

A couple other things I noticed. When I removed the radiator cap and started the motor, antifreeze would push out of the radiator. And when I turned the engine off, the same thing happened. Also, I noticed the reserve tank doesnt have a cap on it, and I dont know if that is under pressure or not.

I think I covered everything Ive noticed. Like I said, I was thinking air in the cooling system, or maybe a bad water pump. I dont have a clutch fan because I've been using a flex fan for quit some time now. Does anyone have any ideas at all here????? Should I try putting a thermostat back in the car???

Thanks all................

Without a thermostat the coolant flows too quickly to allow the radiator time cool down the coolant. If you had heat before removing the thermostat then you probably have air trapped in the system. Are both heater hoses getting about the same temperature (quite warm). You may have a head gasket problem allowing air to get into the system and pushing the coolant out of the radiator. A good shop can check for combustion gasses in the cooling system. Install a new thermostat first and see if that cures your problem.

Check for a clogged radiator. Bleed cooling system and make sure it is full. If there are no problems with the cooling system, then running without a thermostat can cause all kinds of running problems from overcooling to overheating.
Old waterpumps can have worn vanes and not circulate coolant very well. Air pockets can prevent coolant from circulating (just ask the guys who worked at three-mile island in the '70's).
Blown head gasket can allow combustion gasses into the cooling system and force coolant out. Do you have a white cloud coming out of your tailpipe? Does the exhaust smell like coolant? Is there coolant in the oil?

Sometimes the coolant bubbling, boiling getting foamy or frothy can indicate the headgasket being either leaking or blown. I hope that is not the case for you as it is expensive and a major job to repair. I hope it is something simple. Also, you need to get a cap on that reserve or overflow tank, since the cooling system needs to be closed all around. Good luck!

Schellie

I put a 195 degree thermorstat on yesterday that I tested before installing, and allowed the cooling system to bleed itself of any air all night. This morning I had to pour a gallon of antifreeze in the radiator. But I'm still running hotter than normal, and no heat coming through the vents. I was thinking the heater core could be clogged, but my mechanic was able to bleed the system and got the heat to work lastnight. Today, when I checked the radiator after driver for awhile, all the antifreeze would gush up while the engine is running.

I'm getting a little frustrated and confused with this Bird, and I'm just about ready to give up on her.

You may have blown the head gasket between the water jacket and the combustion chambers. Take a look at your spark plugs to see if there is a cylinder that is not burning properly. Do a compression test on the motor. Pressure test the cooling system to see if there is a leak in the cooling system. Check the cooling system for hydrocarbons.

It seems as though the radiator was clogged. I flushed it and I also needed a thermostat gasket, which I didnt have, I only had silicon sealing the thermostat in. I get heat inside now, and its not overheating anymore. It does run a little hotter than before, but I hope thats do to switch from a 180 degree thermostat to a 195 degree thermostat. But, with the radiator flush and the thermostat gasket everything seems normal now....

Hope everything stays normal.......... Thanks Everyone!!!!!!!!!