Operate tester pump (1) to apply 110 kPa (16 psi) pressure to system. If hoses enlarge excessively or bulges while
testing, replace as necessary. Observe gauge pointer and determine condition of cooling system according to fol-
lowing criteria:
Holds Steady: If pointer remains steady for two minutes, serious coolant leaks are not present in system. However,
there could be an internal leak that does not appear with normal system test pressure. If it is certain that coolant is
being lost and leaks cannot be detected, inspect for interior leakage or perform Internal Leakage Test.
Drops Slowly: Indicates a small leak or seepage is occurring. Examine all connections for seepage or slight leak-
age with a flashlight. Inspect radiator, hoses, gasket edges and heater. Seal small leak holes with a Sealer Lubricant
(or equivalent). Repair leak holes and inspect system again with pressure applied.
Drops Quickly: Indicates that serious leakage is occurring. Examine system for external leakage. If leaks are not
visible, inspect for internal leakage. Large radiator leak holes should be repaired by a reputable radiator repair shop.
INTERNAL LEAKAGE INSPECTION
Remove engine oil pan drain plug and drain a small amount of engine oil. If coolant is present in the pan, it will
drain first because it is heavier than oil. An alternative method is to operate engine for a short period to churn the
oil. After this is done, remove engine dipstick and inspect for water globules. Also inspect transmission dipstick for
water globules and transmission fluid cooler for leakage.
WARNING: WITH RADIATOR PRESSURE TESTER TOOL INSTALLED ON RADIATOR, DO NOT ALLOW PRES-
SURE TO EXCEED 124 KPA (18 PSI). PRESSURE WILL BUILD UP QUICKLY IF A COMBUSTION LEAK IS
PRESENT. TO RELEASE PRESSURE, ROCK TESTER FROM SIDE TO SIDE. WHEN REMOVING TESTER, DO
NOT TURN TESTER MORE THAN 1/2 TURN IF SYSTEM IS UNDER PRESSURE.
Operate engine without pressure cap on radiator until thermostat opens. Attach a Pressure Tester to filler neck. If
pressure builds up quickly it indicates a combustion leak exists. This is usually the result of a cylinder head gasket
leak or crack in engine. Repair as necessary.
If there is not an immediate pressure increase, pump the Pressure Tester. Do this until indicated pressure is within
system range of 110 kPa (16 psi). Fluctuation of gauge pointer indicates compression or combustion leakage into
cooling system.
Because the vehicle is equipped with a catalytic converter, do not remove spark plug cables or short out cylinders
to isolate compression leak.
If the needle on dial of pressure tester does not fluctuate, race engine a few times to check for an abnormal amount
of coolant or steam. This would be emitting from exhaust pipe. Coolant or steam from exhaust pipe may indicate a
faulty cylinder head gasket, cracked engine cylinder block or cylinder head.
A convenient check for exhaust gas leakage into cooling system is provided by a commercially available Block Leak
Check tool. Follow manufacturers instructions when using this product.
COMBUSTION LEAKAGE TEST - WITHOUT PRESSURE TESTER
DO NOT WASTE reusable coolant. If solution is clean, drain coolant into a clean container for reuse.
WARNING: DO NOT REMOVE CYLINDER BLOCK DRAIN PLUGS OR LOOSEN RADIATOR DRAINCOCK WITH
SYSTEM HOT AND UNDER PRESSURE. SERIOUS BURNS FROM COOLANT CAN OCCUR.
Drain sufficient coolant to allow thermostat removal. (Refer to 7 - COOLING/ENGINE/ENGINE COOLANT THER-
MOSTAT - REMOVAL). Remove accessory drive belt (Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
Add coolant to radiator to bring level to within 6.3 mm (1/4 in) of top of thermostat housing.
CAUTION: Avoid overheating. Do not operate engine for an excessive period of time. Open draincock imme-
diately after test to eliminate boil over.
Start engine and accelerate rapidly three times, to approximately 3000 rpm while observing coolant. If internal
engine combustion gases are leaking into cooling system, bubbles will appear in coolant. If bubbles do not appear,
internal combustion gas leakage is not present.
7 - 6
COOLING
KJ