Car getting real hot....

ir3333 said

here's my 2 cents...and i've been wrong before.
The thermostat sets the maximum temperature and starts to open when that temperature is reached.The temperature will continue to rise about 5 or 10 degrees until coolant from the rad lowers the temperature in the heads and cylinders.The thermostat never fully closes after the initial opening and the temperature will not change from then on.The speed of the coolant must be reduced to a level that keeps it in the rad long enough for the heat to be dissipated by the rad, usually about 30 degrees (Delta T) If your cooling system is not adequate the temperature will rise when conditions become more severe like a stop and go traffic.
The heat exchanger or rad and fan are the only items cooling the engine temperature if all else is working correctly
Monkey around changing flow ,thermostat or other components is like throwing darts and you may end up with a system that works great or a whole pile of grief!

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ir3333, the thermostat controls the minimum operating temperature in a running engine. At startup the thermostat is closed. To allow circulation and prevent hot spots the bypass allows coolant to circulate. When the coolant gets up to the thermostat opening temp, it begins to open allowing a bit to flow to the radiator.The full open temp is generally about 20°above the advertized temp. The design Delta T across the radiator is generally 10°F to 20°F.
After searching more, the A/C water pump has fewer vanes but the pulley ratio is different to speed up the fan speed to draw more air. The lower vane count on the WP impeller keeps the coolant flow similar and prevents cavitation in the pump.
For the problem that started this, it appears from his photos that the shroud and fan spacing is a major factor. Making a "die" and rounding the inside diameter to bend the aluminium toward the engine will help airflow. This should be just 1/2" around the perimeter of the fan hole. The the fan should be spaced ahead a bit or the shroud spaced back a bit, to get the fan 1/4 to 1/2 inside the shroud and the rest outside. If it still gets warm the A/C WP and pulleys should be installed.