Engine Runs Cold; Coolant Loss; Helm Panel Display - Yanmar BY Series Service Manual

Troubleshooting Chart
12/05

Engine Runs Cold

Problem / Symptom
Instrument Shows Low Temperature

Coolant Loss

Problem / Symptom
Repeated Low Coolant Level
Coolant Forced Out of Coolant Recovery
Tank
White Smoke when Engine is Hot
Indicates Water Vapor

Helm Panel Display

Problem / Symptom
No Display
BY Service Manual
Cause
Defective sensor / instrument
Defective thermostat
Cabin heater / boiler too large
Cause
Defective cylinder head gasket (external
leakage)
External leakage at connection
Turbocharging pressure enters cooling
system via leaking charge air cooler
Defective cylinder head gasket (internal
leakage)
Crack in cylinder head (not cracks
between valve seats)
Cracked cylinder wall
Leaking cylinder head gasket
Cause
Harness connector loose
Defective diode V1
© 2009 Yanmar Marine International
TROUBLESHOOTING
Action
Repair as necessary
Replace
Replace with smaller unit or remove
Action
Replace
Repair as necessary
Repair / replace as necessary
Replace
Repair as necessary
Repair as necessary
Replace
Action
Repair as necessary
Replace
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