Oldsmobile/Buick Repair: Overheating, 1987 oldsmobile toronado, head gasket leak

Question
1987 oldsmobile toronado 3.8. Normally overtheating I would replace the thermostat, but this case it has not resolve the problem. I will tell what has done recently, and what has been replace.
I first try replacing the thermostat, but it still overheating. I did try couple of thermostat includeing gm.I try make sure that I don't have any air pockets left in the system. I also don't get any heat. If I remove the thermostat It does not overheat. I can see flow of water/anti-freeze in the radiator without the thermostat. The heater core has been replace roughly 2-3 year ago. The water pump has been replace recently. I just replace the radiator (leaking). The overfill tank has been clean out. The cap I just replace.  Just about all the hoses have been replace over the last couple of years. The electric fan comes on about 210 degrees according to the  internel computers. As it overheating, I never feel the top hose get warm, and when I remove the thermstat, I don't any amount of fluid behind it.

If I run it without the thermostat the top hose will get warm, along with the heater hoses. I have flush out the system, but I have not back flush system. Some one suggested that my problem is the bcm computer. I had pressure check done to the system, they believe I don't have head gasket leak.

I been trying to this 14 to 20 degree weather, does that make it harder to get the air bubble out?

    Thanks in advance!!

Answer
Hello Jeff,
In 88, there was a problem with some truck water pump replacements that turned out to be the wrong pump.
That is about when the serpentine belts came out, and if the pump is driven by the flat side of the belt, it turns in the opposite direction than a pump designed to be turned by the grooved side of the belt.
If the system is completely filled, it will somewhat work turning backwards, but not correctly, and the thermostat opening will create a problem.

If you think there is any way that might be possible, remove the thermostat housing, and while it is off, start the engine for just a couple seconds, and make sure the water pump pushes coolant up out of the engine, and not out of the radiator hose.

Strange, but possible.

Van