102 4 ENGINE SYMPTOMS DIAGNOSTICS
Combustion Leaks to Coolant
Symptom
Combustion leaks can be identified by coolant
overflowing from deaeration tank or air bubbles in the
coolant.
Cause
• Failed injector sleeve
• Failed air compressor
• Failed head gasket
• Failed EGR cooler
• Porous or cracked cylinder sleeve
The likely cause of combustion gas leakage to
the cooling system is past the injector sleeve in the
cylinder head . A failed c ylinder head g asket or porous
/ cracked cylinder sle eve is possible. However, this
should not be considered unless there is evidence of
engine overheating or high engine m ileage without
proper coolant conditioning.
Tools
• Radiator pressure testing kit
• Plastic surge tank cap a dapter
• Cylinder head test plate
• Water supply housing pressure adapter
• Thermostat opening pressure adapter (cylinder
head)
• Hose pinch-off plie rs (2)
Procedure
1. Is the engine equipped with an air compressor?
•Ifyes,dostep2.
• If no, do step 3.
Figure 110 Air compressor coolant hoses
2. Close off both coolant hoses for the air
compressor with hose pinch-off pliers. Test
the system again.
• If coolant continues overflowing from the
deaeration tank, do step 3.
• If coolant stops overflowing from deaeration
tank, repair or replace the air compressor.
3. Remove injectors following the procedure in the
Engine Service Manual.
Figure 111 Cylinder head cut-away with injector
sleeve
EGES-270-1
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.
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