Cooling System; Checking The Cooling Liquid Level - KTM ENDURO 640 LC4 Owner's Manual

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

Cooling system

Coolant is circulated by a water pump located in the engine. When the engine
is cold the cooling liquid circulates only through the cylinder and the cylin-
der head. After the engine has reached its operating temperature (about 70°C,
158°F), the thermostat opens and the cooling liquid is also pumped through
both aluminum radiators.
Air blowing in through the radiators cools the cooling liquid. The slower the
speed of the motorcycle, the less the cooling liquid is cooled down. Dirty radi-
ator fins also reduce the cooling efficiency.
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 , the fan [1] on the left radiator will switch
on. This fan will provide additional air circulation through the radiator thereby
preventing the cooling system from overheating.
THE RED TEMPERATURE WARNING LAMP FOR THE COOLING LIQUID [2] WILL BEGIN
TO BLINK WHEN THE COOLING LIQUID HAS REACHED APPROX. 120°C (246°F),
EXCEEDING THE NORMAL OPERATING TEMPERATURE.
POSSIBLE CAUSES:
– SLOW RIDING WITH LARGE LOADS AT A HIGHER AIR TEMPERATURE:
IF POSSIBLE INCREASE YOUR RUNNING SPEED, SO THAT MORE AIR CAN BLOW
THROUGH THE RADIATORS. SHOULD THE WARNING LIGHT STILL BE ON OFF
AFTER 300 METERS, STOP IMMEDIATELY, SWITCH OFF THE ENGINE AND LOOK
FOR OTHER POSSIBLE CAUSES.
– TOO LITTLE COOLING LIQUID IN THE SYSTEM:
LET THE ENGINE COOL DOWN, AND CHECK THE SYSTEM FOR LEAKAGE'S. ALSO
2
EXAMINE THE COOLING LIQUID LEVEL CAUTION SCALDING HAZARD! DO NOT
DRIVE ON, UNTIL THERE IS SUFFICIENT LIQUID IN THE COOLING SYSTEM.
GO TO YOUR NEAREST KTM GARAGE AND GET IT SEEN TO. IF YOU DRIVE WITH
THE COOLING LIQUID TEMPERATURE WARNING LIGHT ON, YOU WILL CAUSE
EVEN MORE DAMAGES TO THE ENGINE.
– THE COOLING FAN ON THE LEFT COOLER IS NOT WORKING:
THE COOLING FAN MUST BE RUNNING, WHEN THE COOLING LIQUID TEMPER-
ATURE IS 98°C AND THE IGNITION IS ON. IF THE FAN IS NOT WORKING, AND
THERE APPEARS TO BE SUFFICIENT COOLING LIQUID, THE ONLY THING YOU
CAN DO IS TO DRIVE ON TO YOUR NEAREST KTM GARAGE AT THE LEAST POS-
SIBLE ENGINE LOAD.
– CONTINUOUS USE OF THE CLUTCH (RIDING THE CLUTCH) AT LOWER SPEEDS.
A mixture of 50% antifreezer and 50% distilled water is used as cooling liq-
uid. How-ever, the anti-freeze protection must be at least -25°C (-13°F).
Aside from antifreezing protection, this mixture also provides great corrosion
protection which is why it must not be replaced by pure water.
3
FOR THE COOLING SYSTEM, USE ONLY HIGH-GRADE ANTIFREEZER (MOTOREX ANTI-
FREEZE). USING LOWERGRADE ANTIFREEZE AGENTS, CAN CAUSE CORROSION
AND COOLANT FOAMING.
Pressure induced by heating of the cooling liquid in the cooling system is con-
trolled by a valve in the radiator cap [3]; a water temperature rising up to
125°C (255°F) is admissible, without fear of problems.

Checking the cooling liquid level

The cooling liquid should be 10 mm (0.4 in) above the cooling elements when
the engine is cold (cf. diagram). In the event of the cooling liquid being drained,
always fill the system before hand, then top off while the engine is running.
– IF POSSIBLE, ALWAYS CHECK LEVEL OF COOLING LIQUID WHEN 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.
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 IMMEDI-
ATELY AND GO SEE A DOCTOR!
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