Service Manual

Crankcase Blowby, Measure ISB, ISBe and QSB (Common Rail [...]
Page 14-48 Section 14 - Engine Testing - Group 14
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WARNING
Wear appropriate eye and face protection when using
compressed air. Flying debris and dirt can cause
personal injury.
With the engine shut off, bleed the vehicle's air system
down by opening the drain cock on the wet tank to release
compressed air from the system.
Disconnect the regulated shop air pressure line, with
pressure gauge, from the air compressor governor/
unloader air signal port.
Connect the air signal line. Refer to the OEM service
manual.
Remove the engine blowby service tool and water
manometer or pressure gauge if the blowby is within
specification.
NOTE: On turbocharged air compressors, make sure to
remove the plug previously installed in the air intake hose
connected to the engine intake manifold.
Connect the air compressor discharge line and air intake
hose from the air compressor.
Exhaust Brake Blowby Contribution:
NOTE: Not all vehicles are equipped with an exhaust
brake.
With the engine blowby service tool and the water
manometer, pressure gauge, or transducer still installed,
measure blowby pressure during exhaust brake operation,
if equipped.
Operate the vehicle going down a long inclined road such
as a highway or interstate off ramp. Begin exhaust brake
operation at rated engine speed while measuring blowby
pressure during exhaust brake operation.