Komatsu PC138USLC Operation & Maintenance Manual page 259

TROUBLES AND ACTIONS
Problem
Abnormal noise generated
(combustion or mechanical)
Engine stops while in work
3 - 204
Main causes
Low grade fuel being used
Overheating
Damage inside muffler
Excessive valve clearance
Clogged pre-filter, main filter
Defective engine and fuel line
Remedy
Change to specified fuel
See "Engine water temperature
gauge indicator is in red range"
above
( Replace muffler)
( Adjust valve clearance)
Replace filter cartridge
( Check, repair)
OPERATION