Cooling System; Checking The Coolant Level; Bleeding The Cooling System - KTM 125 SX Owner's Manual

MAINTENANCE WORK ON CHASSIS AND ENGINE
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10 mm
when engine ist cold
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Cooling system

The water pump [1] in the engine circulates the cooling liquid. The cooling
liquid is cooled by the air stream. This means that the cooling effect decreases
with the traveling speed. Dirty radiators additionally reduce the cooling effect.
Pressure induced by heating of the coolant in the system is controlled by a
valve in the radiator cap [2]; a water temperature rising up to 120° C
(248° F) is admissible, without fear of problems.
– If possible, always check level of cooling liquid when engine is cold. If
you have to open the radiator cap [2] when the engine is hot, use a rag to
cover the cap and open slowly to release pressure.
Caution - scalding hazard.
– Do not detach any radiator hoses while the engine is hot. The escaping
hot coolant and the steam may cause serious burns.
– In case you get burnt, hold the affected part of your body under running
cold water right away.
– Coolant is toxic. Keep the coolant out of the reach of children.
– In case coolant is ingested, consult a doctor immediately.
– If coolant gets into your eyes, rinse them out with water immediately and
go see a doctor.
Use a mixture of 40% antifreeze and 60% distilled water for the cooling liq-
uid. The antifreeze should be designed for temperatures of at least -25°C. This
mixture offers frost protection as well as good corrosion protection and should
not be replaced by water alone.
For the cooling system, use only with high-grade antifreeze (e.g. Motorex Anti-
Freeze). Using lower-grade antifreeze agents can cause corrosion and coolant
foaming.

Checking the coolant level

The coolant should be 10 mm (0.4 in) above the radiator fins when the engine
is cold (see diagram). In the event of the coolant being drained, always fill
and bleed the system.
If possible, always check the level of cooling liquid when the engine is cold.
If you have to open the radiator cap when the engine is hot, use a rag to cover
the cap and open slowly to release pressure.
The cooling system must be bled after draining the cooling liquid or after adding
more than 0.25 l (0.06 US gallons) cooling liquid.

Bleeding the cooling system

By removing the screw [3] at the water pump cover you can drain the coo-
lant.
To bleed the cooling system, add coolant up to approx. 10 mm above the radia-
tor fins when the engine is cold.
After a short ride, check the coolant level once more.
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