What can make an engine overheat

Overheating is caused by anything that leads to a loss of coolant, prevents the cooling system from getting rid of heat, or causes excess heat in the engine itself:

 ·         Coolant leaks (water pump, radiator, heater core, hoses, freeze plugs, head gasket, engine internal).

 ·         Weak radiator cap (does not hold rated pressure and allows coolant to boilover). Pressure test the cap to check it out.

 ·         Cooling system clogged (deposits built up in radiator or in engine due to maintenance neglect or use of hard water). Use a cleaner, then reverse flush the system to clean it out. A badly-clogged radiator may need to be rodded out or replaced.

 ·         Thermostat stuck shut (replace).

 ·         Inoperative electric cooling fan (check fan motor, relay and temperature switch for correct operation).

 ·         Bad fan clutch (replace if slipping, leaking or loose).

 ·         Missing fan shroud (reduces cooling efficiency of fan).

 ·         Slipping fan belt (tighten or replace).

 ·         Too low or too high a concentration of antifreeze (should be 50/50 for best cooling).

 ·         Bad water pump (impeller eroded or loose - replace pump).

 ·         Collapsed radiator hose (check lower hose).

 ·         Debris in the radiator (remove bugs and dirt).

 ·         Late ignition timing (reset to specs).

 ·         Restricted exhaust system (check intake vacuum readings and inspect converter, muffler and pipes).

 ·         Radiator and/or fan undersized for application (increase cooling power by installing larger radiator and/or auxiliary cooling fan).