Myth: My engine will make more power with a 160-degree thermostat.
Truth: The hotter you can run your engine without failing parts, the more efficient and powerful it will be. A common misconception is that a cooler thermostat equates to cooling the induction charge, resulting in more power. These two things must not be confused. It's true that cool, dense air coming into the induction system will allow you to burn more fuel and make more power. But, it is also true that your engine is a heat-generating devise. The heat it produces is converted to power by using the rapid expansion of the burning combustion gasses to force the piston down. Of the total heat produced by your engine, the more of it that you can use to force the piston down, the more power you will make. So, isn't all the heat used to move the piston? No, some goes out the exhaust system and some is transferred into the cooling system through the combustion chamber, cylinder walls, oiling system, and other components. So, the hotter the cylinder walls, combustion chambers, and other parts are, the less heat they will absorb in a given amount of time. This means that less heat will be transferred to the cooling system, making it available for the production of power. Additionally, a hotter engine pays dividends in the areas of fuel atomization and friction.
Q. How hot is hot?
A. Most people have been led to believe that 180-190 degrees is ideal, so they start to panic at about 200 degrees. Wrong. If we assume that your cooling system can maintain an operating temperature within about a 30-degree range under most driving conditions, then you should select a thermostat that will keep the operating range in the 190- to 220-degree range. Parts failure on a properly maintained engine should not be a consideration until water temperatures reach 250 degrees or higher.
Q. Is 220 degrees too hot? My car boils over.
A. Your radiator cap is designed to maintain cooling system pressure. This increase of pressure keeps the water/coolant mixture from boiling as the temperature rises above the natural boiling point of water. When the pressure in the system is greater than the cap's designed pop-off pressure, coolant will be released. When this happens, pressure in the system is decreased, allowing the coolant to boil, increasing the pressure, causing the cap to release coolant, lowering the pressure...see a trend here? Whenever a new engine is installed, use a new radiator cap. If your system is boiling over at a temperature within the 190- to 220-degree range, try replacing your radiator cap with a new one or one with a higher-rated pressure.
GMPP recommends that a new radiator, preferably a four-row unit, be installed when installing a new crate engine. If possible, a five- or seven-blade mechanical fan with a clutch should be used with a proper fan shroud. If an electric fan is used, construct a shroud that covers the entire radiator. Select electric fans that move the greatest amount of air and have a high fan speed. The thermostat is then used to "tune" the system, and will determine the operating temperature range for your engine.
Q. How much more power will my crate engine make if I add oil additives? And how much longer will it last?
A.GM has not been able to confirm that any oil additives increase power or durability. A quality engine oil supplement, like GM EOS, is recommended during break-in, but no additives are required after that. If you feel a need to improve your engine's performance or longevity, GMPP recommends synthetic oil. Tests have shown that the film strength of synthetics is superior to dinosaur-based oil, which can help protect your engine in a low oil pressure or severe-duty situation.
Q. My engine uses excessive oil.What's wrong?
A. You must use a proper PCV (positive crankcase ventilation) system. This consists of a PCV valve connected to manifold vacuum and a breather open to the atmosphere. This will evacuate pressure from the crankcase so that oil is not forced by the piston rings. Also, if you change your valve covers, be sure to install covers that use internal oil baffles. Otherwise, the PCV system will draw oil into the intake manifold. Covers that don't have baffles should use a PCV grommet/baffle combination.