I checked the old, and new thermostats by throwing them in a tub of boiling water on the stove. They both worked perfectly on the stove. At around 190, they open, which is where it is supposed to open, according to the Haynes repair manual I have.

I've never installed a thermostat before, so I may be doing something wrong. I point the spring side towards the engine, and the arrow that says "<- TO RAD" is pointed towards the radiator. There is a little plastic rubber gasket thing that was on the old thermostat that looks like it holds the thermostat in place in the housing, so I threw it on. The thermostat w/ rubber ring doesn't fit into the housing properly without applying a little WD-40 to the outer edges of the ring. Then I mount the thermostat in its housing on the engine with gasket and RTV, reattach hoses, and fill with coolant.

Then I turn the car on, let it idle for a couple minutes and watch the coolant level in the radiator. It doesn't really move anywhere. The heat gauge goes up to 158 mark, then I take it out of my driveway. The heat starts going up, and up, and does not come back down. So I pull back into my driveway after going three or four houses down the block because the heat is nearing the top. The fan doesn't seem to help. I feel the radiator and the upper hose is hot, and the upper corner of the radiator. The rest of the radiator is cold (which is why I thought it was a clogged radiator and/or broken water pump).

 

bubbles in the rad would indicate a craked head or a blown head gasket. also have you tried replaceing your temp sensor?

 

Caution. Running without thermostat is a mistake. You want your engine to warm up quickly to the optimal temperature otherwise it is very sluggish, dramatically increase the wear let alone pollution. A thermostat does that job, it keeps coolant in the close loop until it reaches 195/180/160 whatever the grade is to be fully open.

A stock replace from Ready-Rad is sufficient unless you did engine upgrades. They produce radiators for Ford dealers as official replacements. Without thermostat it runs well then it could mean a defective thermostat. 195 is the highest grade, nothing above that.

I will be concerned on that brownish coolant tho...

 

The problem when I put a new thermostat in is that it seems like the coolant doesn't circulate. Is there a special way to bleed the system that I'm not doing or something?

 

After you filled the coolant did you jack up the car? You want to get rid of any air that might be trapped in the system as this could hinder coolant circulation. Jack up the drivers side of the car to make the radiator cap the highest point in the system, turn your heater controls to full heat and run the engine for a bit to allow the air to escape the system.

Also, it might be a far cry, and would not explain why it all started when maintaining your a/c, but make sure you have the correct pump. I seem to recall there are some pumps that have the impeller fins pointed in the opposite direction for a belt setup that turns the pump the other way. Just a thought!

 

Did you ever have any luck with the overheating?