Cooling system knowledgments.

[Fernando Mendes]

"The basis of cooling system coolant is fresh,clean water to which must be added a rust preventive compound and antifreeze solution when necessary.To remove the radiator filler cap loosen slowly,particularly when engine is HOT.Turn cap in clockwise direction until reaches first stage or the safety stop.In this position cap should be loose so that it can be pressed down AGAINST GASKET approximately 1/8 inches.If escaping air or steam is heard REMOVE HAND from filler cap UNTIL IT STOPS.After steam and pressure have been released press the cap downward,turn to the extreme left,then lift it off.Vehicle should be standing on fairly level ground before starting to fill radiator.If system is empty,fill radiator until liquid can be seen through filler neck.If the system is filled with COLD liquid the thermostat will close even though the engine is warm.THIS ACTION MAY TRAP AIR IN CYLINDER BLOCK AND HEAD.THE TRAPPED AIR WILL LEAK THROUGH THERMOSTAT VENT HOLE,THEREBY LOWERING LIQUID LEVEL IN RADIATOR.Additional coolant shoud then be slowly added until no further air bubbles are noticed.This method should be used if more than two quarts are necessary to refill radiator.ALWAYS FILL RADIATOR UNTIL LIQUID IS VISIBLE THROUGH NECK.If engine is cold,a loss of approximately one quart will result.If engine is warm no appreciable loss will be noticed.Do not overfill radiator when antifreeze solution are used.Normal expansion of heated water causes level to rise.When engine is stopped and water cools,contraction of liquid lowers level.It is this apparent low level which might indicate the need of additional fluid.WATER IN SYSTEM SHOULD BE HOT BEFORE ANY CHECK OF LEVEL IS MADE"
TM9-801 GMC 1944 WWII.