Car getting real hot....

Snake said
part guy sold me a motorad cap #10234, i ask for a 16 pound,but in the center its stamp 18, wrong cap? my car almost overheated yesterday.thanks for the high jack.

A higher pressure rad cap wilnot make an engine overheat. It does raise the boiling point of the coolant. The addition of antifreeze also raises the boiling point, but caution needs to be exercised here. Water transfers heat the best but you need other aditives for the cooling system. Corrosion inhibitors and something to lube the WP seal.
Yellow rose is mostly correct; the thermostat controls the minimum operating temperature of your engine. How hot it gets is a composition of a number of factors such as ambient temp, compression, air/fuel ratio, etc. The bottom line is if the cooling system is designed correctly it should not overheat. That term is not exactly a temperature factor. What temp can the rings tollerate without loosing tension, before the pistons get tight in the bore, etc. As long as the radiator is large enough to dissipate the generated heat, that is good. But then airflow to remove the heat from the radiator is required. This entails a large enough fan and in most cases a shroud. Fan speed and design are also factors. To a point the faster you can spin the fan the more air it will draw, but centrifugal force limits that. On an A/C equiped vehicle, the condenser transfers heat to the air that subsequently is required to cool the radiator. Increasing the airflow solves this problem with different pulley ratios to turn the fan faster. Because the pulley also turns the WP it also turns faster. This could cause cavitation in the WP. This I believe is why the pumps have fewer vanes. It would be interesting to know what the actual flow rate through the cooling system is between the large diameter WP pulley and more vanes and the smaller pulley and fewer vanes on the same vehicle would be. Seems I remember the A/C cars generally can with a higher capacity radiator, so that would have to be installed. A turbine flow meter and a totalizer could be installed in the upper rad hose with the totalizer remotely in the cabin. Turbines are sized by a number of volumns with gallons per minute being one. Knowledge of the approximate GPM in the cooling system.would be required. The turbine size is basically turbine diameter in inches or millimeters. The spec may be in GPH but is easily converted to per minute. One popular turbine on oil sites is 27 to 270 gallons per hour, which if memory serves me is a 1". There are many more sizes. If the flow rate is lower than the minimum, fluid will pass through without spinning the turbine appropriately. Too high a flow rate will damage the turbine.