Service Manual

ISB, ISBe and QSB (Common Rail [...] Cooling System Diagnostics
Section 8 - Cooling System - Group 08 Page 8-57
To buy Cummins Parts and Service Manuals, Training Guides, or Tools go to our website at https://store.cummins.com
Operate the engine at rated rpm until it reaches a
temperature of 82°C [180°F].
Check for a continuous flow of air bubbles from the hose
in the water container.
NOTE: The engine coolant temperature must be stable to
perform this test. An increasing coolant temperature will
give a false indication of air due to expansion of the
coolant in the system.
Analyzing the Data
Check the color of fluid in the combustion gas leak tester.
A yellow or green color will indicate a combustion leak. A
blue color will indicate there is no leak. This information
will help isolate the source of air in the cooling system, if
any.
NOTE: The test kit is not sensitive enough to detect very
small combustion gas leaks.
Do not rule out combustion gas leaks if the combustion
gas leak test does not indicate a combustion gas leak.
Worksheet
Fill in the blanks with the test data as the test is being run. Record the cylinder head coolant pressure and cab gauge
coolant temperature reading at each of the thermostat housing temperature points listed on the left side of the matrix
below. Mark when the radiator line gets hot, when the fan starts operating, and when the shutters open.
Coolant
Temperature
Pressure
Thermostat
Housing
Cab Gauge Cylinder Head Radiator “In
Line” Starts
Getting Hot
Fan Starts
Operating
Shutters Open Notes
140 Engine at high
idle throughout
test
145 Monitor for air
throughout test
150
155 Start
monitoring
radiator “in”
line
160
165
170
175
180
185
190
195