KTM 125 SX 2023 Owner's Manual page 128

21 TROUBLESHOOTING
Faults
Engine overheats
Malfunction indicator lamp
lights up or flashes
White smoke emission (steam
in exhaust gas)
Gear oil exits at the vent hose
Water in the gear oil
126
Possible cause
Too little coolant in cooling sys-
tem
Too little air stream
Radiator fins very dirty
Foam formation in cooling sys-
tem
Damaged cylinder head or
cylinder head gasket
Bent radiator hose
Thermostat defective
Malfunction in the electronic
fuel injection
Damaged cylinder head or
cylinder head gasket
Too much gear oil added
Damaged radial shaft seal ring
or water pump
Action
–
Check the cooling system for leakage.
–
Check the coolant level. (
–
Switch off engine when stationary.
–
Clean the radiator fins.
–
Drain the coolant. ( p. 100)
–
Refill with coolant. (
–
Check the cylinder head and cylinder
head gasket.
–
Change the radiator hose.
–
Check the thermostat.
Guideline
Opening temperature: 70 °C (158 °F)
–
Check the wiring for damage and the
electrical plug-in connections for corro-
sion and damage.
–
Read out the fault memory using the
KTM diagnostics tool.
–
Check the cylinder head and cylinder
head gasket.
–
Check the gear oil level. (
–
Check the radial shaft seal ring and the
water pump.
p. 100)
p. 101)
p. 118)