2001 YAMAHA YFM660R engine overheat

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Coolant temperature warning light “ ”
When the coolant temperature reaches a spec-
ified level, this light comes on to warn that the
coolant temperature is too hot. If the light
comes on during operation, stop the engine as
soon as it is safe to do so and allow the engine
to cool down for about 10 minutes.
The coolant temperature warning light circuit
can be checked according to the procedure on
page 4-7.
CAUTION:


The engine may overheat if the ATV is
overloaded. If this happens, reduce the
load to specification.


Restart after making sure that the light is
out. Continuous use while the light is on
may cause damage to the engine.

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WARNING


Always set the parking brake before start-
ing the engine. The ATV could start mov-
ing unexpectedly if the parking brake is
not applied. This could cause loss of con-
trol or a collision.


Always be sure you have released the
parking brake before you begin to ride.
The brake could overheat if you ride the
ATV without releasing the parking brake.
You could lose braking performance
which could cause an accident. You could
also wear out the brakes prematurely.

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Cooling system
1. Check the coolant level in the coolant res-
ervoir when the engine is cold as the cool-
ant level will vary with engine temperature.
The coolant level should be between the
maximum and minimum marks.
2. Remove the coolant reservoir cap, and
then add coolant or distilled water to raise
it to the specified level.
CAUTION:
Hard water or salt water is harmful to the en-
gine. You may use soft water if you can’t get
distilled water.
NOTE:
If water is added, have a Yamaha dealer
check the antifreeze content of the coolant
as soon as possible.
The radiator fan operation is completely au-
tomatic. It is switched on or off according to
the coolant temperature in the radiator.
If your ATV overheats, see page 8-120 for details.Coolant reservoir capacity:
0.29 L
1. Coolant reservoir cap
2. Maximum level mark
3. Minimum level mark
1. Cache du vase d’expansion
2. Repère de niveau maximum
3. Repère de niveau minimum
1. Tapa del depósito de líquido refrigerante
2. Marca de nivel máximo
3. Marca de nivel mínimo

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NOTE:
The air filter element should be cleaned every
20 ~ 40 hours. It should be cleaned and lubri-
cated more often if the machine is operated in
extremely dusty areas. Each time the filter ele-
ment maintenance is performed, check the air
inlet to the filter case for obstructions. Check
the air cleaner rubber joint to the carburetor
and manifold fittings for an airtight seal. Tight-
en all fittings securely to avoid the possibility
of unfiltered air entering the engine.
CAUTION:
Never operate the engine with the air filter el-
ement removed. This will allow unfiltered air
to enter, causing rapid engine wear and possi-
ble engine damage. Additionally, operation
without the filter element will affect carbure-
tor jetting with subsequent poor performance
and possible engine overheating.
1. Hose
1. Flexible
1. Manguera

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Engine overheating
NOTE:
If it is difficult to get the recommended coolant, tap water can be temporarily used, provided that it
is changed to the recommended coolant as soon as possible.
WARNING
Wait for the engine and radiator to cool before removing the radiator cap. You could be burned by
hot fluid and steam blown out under pressure. Always put a thick rag over the cap when opening.
Allow any remaining pressure to escape before completely removing the cap.
Wait until the
engine has cooled.Check the coolant level in the
reservoir tank and/or radiator.
Level is OK.
Level is low, check the
cooling system for leakage.
No
leakage.
Leakage.Ask a Yamaha dealer to inspect
and repair the cooling system.
Add coolant. (See NOTE.)
Restart the engine. If the engine overheats again, ask a
Yamaha dealer to inspect and/or repair the cooling system.