Table of Contents
Advertisement
7 - 1 4
COOLING SYSTEM
•
TESTING COOLING SYSTEM FOR LEAKS
ULTRAVIOLET
LIGHT
METHOD
A leak detection additive is available t h r o u g h t h e
parts department t h a t can be added to t h e cooling
system. The additive i s h i g h l y visible under u l t r a v i -
olet l i g h t (black l i g h t ) . Poor one ounce o f additive
i n t o t h e cooling system. Place t h e heater control u n i t
i n " H E A T " position. S t a r t and operate the engine u n -
t i l t h e radiator upper hose is w a r m t o the t o u c h . A i m
t h e black l i g h t , tool 7138 or a n equivalent, a t t h e
components t o be checked. I f leaks are present, t h e
black l i g h t w i l l cause t h e additive t o glow a b r i g h t
green color.
The black l i g h t can be used i n conjunction w i t h a
pressure tester t o determine i f any e x t e r n a l leaks ex-
ist (Fig. 6).
Fig. 6 Leak Detection Using Black Light—Typical
PRESSURE
TESTER
METHOD
The engine should be a t the n o r m a l o p e r a t i n g t e m -
perature. Recheck t h e system cold i f t h e cause of
coolant loss is n o t located d u r i n g w a r m engine exam-
i n a t i o n .
WARNING: HOT, PRESSURIZED COOLANT
CAN
CAUSE INJURY BY SCALDING.
Carefully remove t h e radiator pressure cap f r o m
the f i l l e r neck a n d check t h e coolant level. Push
down on the cap to disengage i t f r o m t h e stop tabs.
Wipe t h e inside of the f i l l e r neck and examine t h e
lower inside sealing seat for nicks, cracks, p a i n t , d i r t
and solder residue. Inspect t h e r a d i a t o r t o reserve
t a n k tube for i n t e r n a l obstructions. I n s e r t a w i r e
t h r o u g h the tube to ensure i t is n o t obstructed.
Inspect the cams on the outside o f the filler neck. I f
the cams are bent, seating o f pressure cap valve and
tester seal w i l l be affected. B e n t cams can be re-
formed i f done carefully. A t t a c h pressure tester 7700-
A or an equivalent t o the r a d i a t o r f i l l e r neck (Fig. 7).
Fig. 7 Pressure Testing Cooling System
Operate t h e tester pump to apply 103.4 k P a (15
psi) pressure t o t h e system. I f the hoses enlarge ex-
cessively or bulge w h i l e testing, replace as necessary.
Observe the gauge pointer and determine the condi-
t i o n of the cooling system according t o f o l l o w i n g cri-
teria.
H o l d s S t e a d y : I f the pointer r e m a i n s steady for
two minutes, there are no serious coolant leaks i n
the system. However, there could be a n i n t e r n a l leak
t h a t does n o t appear w i t h n o r m a l system test pres-
sure. I f i t is certain t h a t coolant is b e i n g lost and no
leaks can be detected, inspect for i n t e r i o r leakage or
perform the Combustion Leakage Test.
D r o p s S l o w l y : Indicates a s m a l l leak or seepage is
occurring. Examine a l l connections for seepage or
slight leakage w i t h a flashlight. Inspect the radiator,
hoses, gasket edges and heater. Seal s m a l l leak holes
w i t h a Sealer L u b r i c a n t , or equivalent. Repair leak
holes and reinspect the system w i t h pressure applied.
D r o p s Q u i c k l y : Indicates t h a t serious leakage is
occurring. Examine the system for e x t e r n a l leakage.
I f no leaks are visible, inspect for i n t e r n a l leakage.
Large radiator leak holes should be repaired b y a
reputable radiator repair shop.
INTERNAL
LEAKAGE
INSPECTION
Remove the engine o i l pan d r a i n p l u g and d r a i n a
small amount o f engine o i l . I f coolant is present i n
the pan i t w i l l d r a i n first because i t i s heavier t h a n
oil. A n alternative method is to operate t h e engine
for a short period to churn t h e o i l , t h e n remove t h e
engine dipstick and inspect for w a t e r globules. Also
inspect t h e transmission dipstick for water globules
and the transmission f l u i d cooler for leakage.
Advertisement
Table of Contents
