2003 Suzuki LT-Z400 Factory Service Manual, Page 273Get this manual
SERVICING INFORMATION
Complaint Engine overheats
Symptom and possible causes
1Carbon buildup on piston crown
CleanCheck level and addReplaceCleanAdjust float heightTighten or replaceChangeSee radiator section
2Insufficient amount of engine oil345678Defective oil pumpClogged oil circuitFloat chamber fuel level too lowAir leakage from intake pipeIncorrect engine oilDefective cooling system
RADIATOR
Complaint Engine overheatsSymptom and possible causes Remedy
Add coolantCleanReplaceCleanBleed out airReplaceReplaceReplaceReplaceInstall radiator coverReplaceReplace
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Not enough engine coolantRadiator core cloggedDefective temperature switchClogged engine coolant passageAir trapped in the cooling circuitDefective water pumpIncorrect engine coolantDefective cooling fan thermo-switchDefective thermostat
Engine overcools