Check the radiator. Look for leaks
on the top tank, front and back of the
core and bottom tank.
Leaks may not show up when
your engine is cold, so look for rust
and odd-colored dribbles where
coolant has leaked and dried.
Later, when you’ve got the engine
running at operating temperature
and pressure, check those places
again for wet spots. Use a flashlight
during both inspections.
Finally, take the radiator cap off.
If the cooling system is hot, open the
filler cap slowly until all pressure is
gone. Use a rag or glove to protect
your bare hand from the hot cap.
The coolant should be at least
over the top of the core. It should be
almost clear—and colored by the
antifreeze.
N
o matter the temperature, your vehi-
cle’s cooling system should be able to
reach 160 to 180°F. If yours won’t,
have the thermostat checked. It may be
stuck open and need replacing.
A vehicle system that always runs at
more than 200°F also needs attention.
A bum thermostat, a clogged radiator,
a bad radiator cap or filthy coolant
may be the culprit. The engine’s air
flow may even be blocked.
To speed up heating in freezing
weather, you can partially cover the air
intake grilles with canvas when start-
ing the vehicle. Be sure to remove the
cover after the engine reaches operat-
ing temperature.
Look at the radiator cap. It should
be the one your TM calls for. Just any
cap won’t do. The pressure rating of
the cap is vital. Too low a rating low-
ers the boiling point of your coolant.
Too high builds up pressure that’ll pop
radiator seams or blow hoses
Hoses need to be touched as well as
looked at. They must withstand heat,
pressure and vibration. They’re rub-
ber, so they rot, harden and crack with
age. That’s why you need both eyes
and hands to detect bad hoses. Report
any bad hoses that show these signs.
Engine Cooling Systems…
Drivers,
when it’s cold
outside, don’t
forget about
your
engine’s
cooling
system.
PS 600
NOV 02
12
Cap pressure
rating correct?
I’m
right
where I
should
be!
Hose clamp
loose, broken,
missing
Hose connection
leak
Oil or fuel
in coolant
Wrong or broken
pressure cap
Hose connection
leak
Hand gasket
leak
Plug
leaks
Seam leak
Seam
leak
Bolt
leak
Hose connection leak
Hose cracked,
brittle, mushy
Coolant in
engine oil—
shows on
dipstick as
blobs of water
Belt cracked,
ragged, loose,
missing
Core leak
Seam leak
Bugs, leaves,
other debris
Drain cock leak
If your coolant is muddy-looking or
has bits of junk in it, your cooling sys-
tem needs draining and flushing, maybe
even cleaning. Report it.
If you see a rainbow of oil slime on
top of the coolant, you’ve probably got a
leak inside the engine. Exhaust gas or
oil is getting into your cooling system.
Pull the crankcase
dipstick and check
for water in the oil.
Little blobs will
show on the dip-
stick. Either way,
report it.
Note, drivers, that air-cooled systems
don’t need much attention. All they need
is a good flow of air—meaning all the
airflow shrouds must be in place.
Water blobs
on dipstick?
Any leaks or other cooling system problems?
Puffy?
Hard
(cracks are
clues)?
Mushy?
Wet
(or even damp)?
600. 12-13 (C)
9/26/02
5:37 PM
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