Download What is the best way to fix a coolant leak

What is the best way to fix a coolant leak
Proper repair depends where the leak is. Coolant leaks often occur at the water
pump shaft seal. Other leak points include radiator, heater cores, hoses, freeze
plugs, and the engine itself.
Small radiator leaks, as well as minor internal seepage inside the engine or past a
freeze plug, can often be temporarily plugged with a can of sealer. No sealer will plug
a leaky water pump, hose or badly damaged or corroded radiator. The only cure is to
replace the faulty component.
Small radiator leaks can often be patched by soldering or using a special hightemperature epoxy. Other options include sending the radiator to a specialty shop for
repair or recoring, or replacing the entire radiator itself with a new one. With a leaky
heater core, replacement is the best option.
Internal coolant leaks are more of a challenge to fix because they require more
expertise to diagnose and repair.
Coolant can seep past a head gasket or hairline cracks in the engine block or cylinder
head and enter the combustion chamber or crankcase.
If not stopped, such a leak can cause major damage to piston rings, cylinders and
bearings, as well as overheating due to coolant loss.
An internal leak may be indicated if the cooling system is losing coolant without
obvious leaks. The first item to check is the radiator cap. A weak cap that can't hold
pressure will allow the system to boil over. Both the cap and radiator should be
pressure checked with a pressure tester.
If the cooling system fails to hold pressure, coolant is leaking internally. The question
is where? A compression check on the engine will tell if a head gasket is leaking or if
there's a hairline crack in the cylinder or head.
A higher than normal dipstick level and/or excessive moisture in the crankcase would
indicate a coolant leak into the crankcase. In either case, major engine work will be
necessary to repair the leak.
Another type of internal leak is one that can occur between the coolant and
automatic transmission fluid (ATF). On most vehicles with automatic transmissions,
ATF is routed through an oil cooler inside the radiator.
If the tubing leaks, coolant can enter the transmission lines, contaminate the fluid
and ruin the transmission. Red or brown drops of oil in the coolant would be a
symptom of such a leak.
Because the oil cooler is inside the radiator, the radiator must be replaced to
eliminate the problem. Transmission fluid should also be changed.