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OM-C3 11/21
Service and Maintenance - 500 Hour
SP 21. Pressure Testing Cooling System
Explosive release of fluids from
pressurized cooling system can
cause serious burns. Shut off
engine. Only remove filler cap
when cool enough to touch with
bare hands. Slowly loosen cap to
first stop to relieve pressure before
removing completely.
Test Coolant Filler Cap
1. Remove coolant filler cap and attach to an appropriate
tester as shown (right).
2. Pressurize cap to 10kPa (1.1 bar) (16 psi) . Gauge
should hold pressure for 10 seconds within the normal
range if cap is acceptable.
If gauge does not hold pressure, replace pressure cap.
3. Remove the cap from gauge, turn it 180°, and retest
cap. This will verify that the first measurement was
accurate.
Test Cooling System
NOTE: Engine should be warmed up to test overall
cooling system.
1. Allow engine to cool, then carefully remove coolant
filler cap.
2. Fill tank with coolant to the normal operating level.
IMPORTANT: DO NOT apply excessive pressure to
cooling system, doing so may damage coolant tank and
hoses.
3. Connect gauge and adapter to filler neck, as shown
(right). Pressurize cooling system to 110kPa (16 psi).
4. With pressure applied, check all cooling system hose
connections, coolant tank, and overall engine for leaks.
If leakage is detected, correct as necessary and pressur
test system again.
If no leakage is detected, but the gauge indicated a drop in
pressure, coolant may be leaking internally within the
system or at the block-to-head gasket. Have your
servicing dealer correct this problem immediately.
!
CAUTION
Coolant filler cap tester
Cooling system/radiator test
