Economical operation of the engine requires maintaining operating temperatures of 170° to 185°F. The lack of enough
coolant can be most expensive, so maintaining a tight non-leaking cooling system cannot be over-emphasized.
Cooling troubles result in either overheating or overcooling, which are caused by the following.
FAN BELT. Broken or loose.
EXTERNAL LEAK. Radiator, cylinder head gaskets, coolant pump seals, thermostat gasket or core plugs. (Watch for
coolant leaks on floor after truck has been stored.)
INTERNAL LEAKS. Cracked block or cylinder head, loose or defective cylinder head gaskets. (Can be noted by raised
oil level in crankcase or by foam on dipstick.)
CLOGGED OR LEAKY RADIATOR. Rusty coolants settle in and clog radiators. Corrosion perforation of the thin metal
and mechanical failure of soldered joints.
DEFECTIVE COOLANT PUMP. Can be checked by watching the action of the coolant in the radiator or by inserting a
sight glass into the upper hose while the engine is idling.
INCORRECT ENGINE TIMING. Check timing if no other causes are found.
POOR DRIVING PRACTICE. Using incorrect transmission speed.
DRAGGING BRAKES. When not completely released-or improperly adjusted.
THERMOSTAT. Check for correct opening temperature.