Service Manual

Cooling System Diagnostics ISB, ISBe and QSB (Common Rail [...]
Page 8-54 Section 8 - Cooling System - Group 08
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Pour the test fluid into the combustion gas leak test
instrument until it is up to the yellow fill line on the
instrument.
Insert the rubber tip of the combustion gas leak test
instrument into the radiator fill neck. Hold the instrument
down firmly and turn back and forth to make certain that
an airtight seal is formed between the tester and the
radiator fill neck.
NOTE: Install the test equipment at the expansion tank
filler neck on Marine applications.
Start the engine and run at high idle for approximately 30
minutes. Monitor the engine temperature and color of the
test fluid during engine operation. Do not allow the engine
temperature to exceed 100°C [212°F] during the test.
If the color of the test fluid changes from blue to yellow or
green anytime during the test, combustion gases are
leaking into the cooling system. Discontinue the test if the
color of test fluid changes from blue to yellow or green.