Service Manual

ISB, ISBe and QSB (Common Rail [...] Air Leaks, Compressed Air System
Section 12 - Compressed Air System - Group 12 Page 12-33
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Operate the engine and check for air leaks.
Air Leaks, Compressed Air System
(012-019)
Initial Check
Verify the unused unloader port, if applicable, on the air
compressor has a pipe plug installed.
Verify all unused ports are plugged with pipe plugs except
for the exhaust port on the air governor. The air governor
exhaust port must always be ventilated to the
atmosphere.
Operate the engine to activate the air compressor.
With the air compressor pumping between 550 to 690 kPa
[80 to 100 psi], use a solution of soapy water to check for
air leaks in the following areas:
• Air compressor head gasket.
• Air compressor cover gasket.
• Fittings and hoses connected to the intake, discharge,
and air governor signal line on the air compressor.
• Fittings and hoses connected at the air governor, wet
tank, and the air dryer.
If air leaks are found at the air compressor head or cover
gasket, verify that the air compressor head and cover
bolts are tighten properly. Refer to Procedure 012-007 in
Section 12.
Shut the engine OFF . Check for air leaks both at key-
OFF and key-ON.
NOTE: Some components at key-ON can make the sound
of an air leak.
Walk around the vehicle and listen for air leaks from the
rest of the air system not already inspected.