Any
indication of overheating is a serious matter, so the best course of action is
to shut down the engine to prevent further damage. Driving a car with an
overheated engine can warp cylinder heads and damage internal engine parts such
as valves, camshafts and pistons.
Even letting
the engine cool for an hour and topping off the radiator with a 50-50 mix of
antifreeze and water may not fix what's wrong. Here are some reasons an engine
will overheat:
− The coolant
level could be extremely low, because of long-term neglect or because a leak
has developed in the radiator or radiator hoses. Coolant circulates inside the
engine block to cool it, and the leak might be in the block, or from the water
pump or heater hoses. Old coolant loses its corrosion-inhibiting properties,
allowing rust to form and ultimately causing damage.
− The
thermostat that allows coolant to circulate may be stuck in the closed position
or a clog may have developed, perhaps from debris in the cooling system.
− The engine
cooling fan has stopped working or the radiator's cooling fins are clogged with
debris so that the air flow that reduces the coolant temperature is restricted.
− The radiator
cap has gone bad and no longer maintains enough pressure in the cooling system,
allowing coolant to boil over (engines normally operate at about 210 to 220
degrees Fahrenheit).
− The head
gasket that seals the gap between the cylinder head and engine block may have
failed, allowing coolant to leak inside the combustion chambers. The steam should
be visible coming out of the exhaust system.
− The water
pump has stopped working or the belt that drives it broke or is slipping and
not pumping enough coolant.
− You've been
towing a 5,000-pound trailer with a vehicle equipped to tow only 2,000 pounds,
exceeding the vehicle's cooling capacity. (You probably also strained the
transmission.)
Checking
your engine coolant level in the overflow tank on a regular basis can help
avoid disasters. If you have to keep topping off the coolant, that's an
indication of a small leak that should be taken care of before it becomes a
major one. Having your coolant tested and the entire system inspected by a
mechanic every couple of years is an even better way to prevent cooling system
disasters.
