The cooling system problems can be detected by one of two ways:
You find a
leak in your driveway
The engine starts overheating.
The cooling system
is not maintenance-free and requires regular checks to stay in good
condition.
LEAKS
There are a lot of flexible connections in the
cooling system and this is where leaks most
commonly start. The rubber hoses will begin to
wear out and the joints will loosen from movement.
A leak can happen anywhere in the system: the
water pump can leak, the radiator can rust through,
or the cylinder block can lose a gasket. Leaks in
hoses can usually be repaired easily, but leaks in big
components like radiators and water pumps
generally require the attention of a professional.
Leaks that aren’t addressed can lead to
overheating, which leads to engine failure. Get a
leak repaired right away.
RADIATOR FAILURE
The coolant in the radiator is mixed with water,
and the water can bring with it minerals and
deposits that will clog and corrode your radiator.
When this happens, the coolant can’t pass through
the tubes of the radiator, and the engine overheats.
If it rusts out, it will eventually drain down and
cause overheating.
A mildly corroded radiator can be flushed with
commercially available products, or some pros offer
a power flush that really gets the radiator clean.
WATER PUMP FAILURE
The water pump is subject to failure in several
ways.
A mechanical pump that is mounted to the
engine may fail at the gasket points where it connects to
the engine.
it may stop working if
the engine belt driving it slips or
breaks.
An electric pump may
fail if its internal motor dies.
The
bearing in the water pump can also give
out.
A whining sound may indicate that a
water pump is about to fail.
THERMOSTAT FAILURE
The thermostat is responsible for
regulating the flow of coolant by
measuring the engine temperature
and opening if the engine needs to be
cooled down. If the thermostat fails
while closed or partially closed, the
car will overheat because the coolant
can’t flow. If the thermostat fails while
open, it will take the engine a much
longer time to come up to temperature,
which can be hard on the oiling system and cause
oil crystallization on the engine
components. Don’t run your car without a
properly functioning thermostat.
WORN-OUT COOLANT
Coolant needs to be topped off or replaced
periodically. You can check the level and condition of
the coolant in the overflow tank. If the level is low,
it can be “topped off ” with distilled water. If it’s
getting brown with contaminants or rust, it’s time to
change the coolant.
HOSE CLAMP FAILURE
Hose clamps usually don’t fail unless they have
been removed and reinstalled. Be careful when
reinstalling hose clamps that have been stretched
— they can fail on reinstallation.
Locating Leaks
Leaks in the cooling system can be internal or external. Internal leaks, where
the coolant is getting into the cylinders and oil pan, can cause serious problems
and should be addressed by a professional. External leaks might be easily
repaired depending on where they are located.
Here are some ways you can locate a leak in your cooling system.
Use a piece of cardboard. If you suspect you have a
leak but aren’t able to locate the source, place a
piece of clean cardboard under the engine area of
your car when you park it for the night. In the
morning, the position of the liquid on the
cardboard should help you find the leak.
Inspect the hoses. Rubber components, like
the hoses, can often develop leaks since they
are designed to flex. Wearing surgical gloves,
gently
run your hands around the cold engine and feel
for leaks on the back sides of the hoses. Check
the hose connections and make sure the hoses are
tightly held in place. Also, check for rusty water
or stains on the hoses. As you go, check your
gloves for the fluorescent color of the coolant.
Inspect the radiator. The radiator is made of thin
metal fins, which can easily be punctured or
rusted. This radiator suffered from a cooling fan
that dug into the middle of the radiator fins.
Corrosion or mineral deposits due to damage
could be a sign of a leak.
Inspect the radiator cap. The rubber seal in the
radiator cap can fail, and the metal backing holding
the seal can crack and allow pressure to be
released. When the engine is cool, inspect the area
around the radiator cap for signs of escaping
coolant. Remove the cap and inspect the underside.
Look for a milky, oily substance—this may be a
sign of an internal coolant leak.
Check the heater core. The heater core is located
inside the passenger compartment, and if it starts to
leak, it may soak the carpeting with coolant, or it
may weep out of the air conditioner drain. If the
inside carpet is getting wet, blot it with a clean
paper towel and look for coolant color or rust.
Check the thermostat housing. Some thermostats
are mounted on the top of the engine where the
hot coolant is returned to the radiator, and this is
a key area for leaks. You can see evidence of a
past
leak here from the mineral and rust buildup on
the aluminum housing and the re-positioned
hose clamp.
Inspect the engine block freeze plugs. The engine is
equipped with something called freeze plugs, which
pop out if the water in the engine begins to freeze
and expand. These freeze plugs can rust out or
weep. Look for signs of rust trailing down from the
freeze plugs.
Check the head gaskets. There is a gasket between
the cylinder block and the cylinder head made of
metal. If it fails, coolant may flood into the
cylinders or it may leak out the side of the gasket.
When this happens, you may see a small stream of
fluid running down the length of the engine.
Check the water pump. A water pump failure can
happen at the gasket between the pump and the engine or at the front bearing on the rotating shaft.
The water pump may have something called a weep
hole, which is a hole near the rotating shaft. This
weep hole is used if the water pump is beginning
to fail.
If the weep hole is leaking oil, it means the front
bearing is failing. If it is leaking coolant, it means
the seals in the pump are failing. If you see
anything coming out of the weep hole, have it
checked right away.
Check the oil. Remove the engine oil dipstick and
look for a white, milky substance. This is a sign
that there is an internal engine leak and you need
to have it checked.
Pressure test the system. Use a radiator pressure
tester to test the system. This is a small pump and
gauge that attaches to the radiator in place of the
cap. Bring the cooling system up to pressure and
monitor the gauge for a couple of minutes. If the
system doesn’t lose too much pressure, there aren’t
any serious leaks. A quick drop of pressure may
confirm an internal leak that you can’t see.
