Checking The Coolant Level; Cooling System - KTM 625 SXC Owner's Manual

MAINTENANCE WORK ON CHASSIS AND ENGINE
40
1
10 mm
when engine is cold
2

Checking the coolant level

The coolant should be 10 mm (0.4 in) above the radiator fins when the engine
is cold (see illustr.). In the event of the coolant being drained, always fill and
bleed the system.

Cooling system

Coolant is circulated by a water pump located in the engine. When the engine
is cold the coolant circulates only through the cylinder and the cylinder head.
After the engine has reached its operating temperature (about 70°C, 158°F),
the thermostat [1] opens and the coolant is also pumped through both alu-
minum radiators.
Air blowing in through the radiators cools the coolant. The slower the speed
of the motorcycle, the less the coolant is cooled down. Dirty radiators also
reduce the cooling efficiency.
625 SMC
If little or no air blows through the radiators, for example when riding through
slow traffic or waiting at traffic lights, the coolant temperature will rise. If the
coolant temperature rises to 98° C (208°F), the fan on the left radiator will
switch on. This fan will provide additional air circulation through the radia-
tor thereby preventing the cooling system from overheating.
– If possible, always check level of cooling liquid when engine is cold. If you
have to open the radiator cap 3 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, go see a doctor immediately!
– If coolant gets into your eyes, rinse them out with water immediately and
go see a doctor!
Possible causes of an overheated engine:
– Slow driving and heavy load at a high air temperature:
Increase your driving speed if possible to allow wind to cool the radiator.
– Not enough cooling liquid in the system:
Allow the engine to cool off and check the system for leaks. Also
check the cooling liquid level, CAREFUL – RISK OF SCALDING!
Only continue driving if there is enough liquid in the system. Stop at an
authorized KTM workshop as soon as possible to have the defect elimi-
nated. If you continue to drive with an overheated engine, you will dam-
age the engine.
– The fan in the left radiator is not running:
The fan should run from a cooling liquid temperature of 98°C (208°F)
whenever the engine is running. If the fan is not running and you have
enough cooling liquid, you can continue to drive to the nearest authorized
KTM workshop, keeping the engine load to a minimum.
– Riding the clutch at lower speeds
A mixture of 50% anti freeze liquid and 50% distilled water is used as coolant.
However, the anti-freeze protection must be at least -25° C (-13° F). This mix-
ture offers anti-freeze protection but also good corrosion protection and should
therefore not be replaced by pure water.
For the cooling system, use only with high-grade antifreeze (Motorex Anti Freeze).
Using lower-grade antifreeze agents, can cause corrosion and coolant foaming.
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.
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