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1.Turn OFF the engine from the idle state then check to see that the rive belt is not
protruding from the pulley width of the drive belt auto-tensioner.
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2.Remove the drive belt (Refer to GROUP 14 - Radiator Fan  ).
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3.Securely insert the spindle handle or ratchet handle with a 12.7 mm insertion angle into
the jig hole of the drive belt auto-tensioner. Turn the drive belt auto-tensioner to the left and
right to check and see that there is no threading.
4.If there are any problems in the procedure 1 or 3, replace the drive belt auto-tensioner
(Refer to ).
5.Install the drive belt (Refer to GROUP 14 - Radiator Fan ).
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The drive belt auto-tensioner can be checked whether it is in good condition by checking
its tension.
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1.Check the drive belt tension (Refer to ).
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2.
| caution |
- When measuring the vibration
frequency, make sure that the engine is cold.
- Measure the vibration frequency after turning the crankshaft clockwise one turn
or more.
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Measure the drives belt tension vibration frequency by the following procedures:
(1)
Connect the special tool microphone assembly (MB992082) to the special tool belt tension
meter (MB992081) of the special tool belt tension meter set (MB992080).
(2)
Press the "POWER" button to turn on the power supply.
(3)
Press the numeral key of "1" and check that "No. 01" appears on the upper left of
the display.
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| note |
This operation is to temporarily set the preset data such as the belt specifications,
because if the measurement is taken without input of the belt specifications, conversion to
tension value (N) cannot be made, resulting in judgement of error.
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(4)
Press "Hz" button twice to change the display to the frequency display (Hz).
(5)
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| caution |
- Do not allow any contaminants
such as water or oil to get onto the microphone.
- If strong gusts of wind blow against the microphone or if there are any loud sources
of noise nearby, the values measured by the microphone may not correspond to actual values.
- If the microphone is touching the belt while the measurement is being made, the
values measured by the microphone may not correspond to actual values.
- Do not take the measurement while the vehicle’s engine is running.
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Hold special tool (MB992080) to the middle of the drive belt between the pulleys (at the
place indicated by arrow), approximately 10 - 15 mm away from the rear surface of the
drive belt so that it is perpendicular to the drive belt (within an angle of ± 15 degree).
(6)
Press the "MEASURE" button.
(7)
Gently tap the middle of the drive belt between the pulleys (the place indicated by
the arrow) with your finger as shown in the illustration, and measure that the vibration frequency
of the drive belt is within the standard value.
Standard value: 88 - 121 Hz
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| note |
To take the measurement repeatedly, fillip the drive belt again.
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(8)
After the completion of the measurement, press and hold the "POWER" button to turn
off the power supply.
3.If not within the standard value, replace the drive belt auto-tensioner (Refer to ).
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1.Check the drive belt tension (Refer to ).
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2.
| caution |
- When measuring the tension,
make sure that the engine is cold.
- Measure the tension after turning the crankshaft clockwise one turn or more.
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Use a belt tension gauge in the middle of the drive belt between the pulleys (at the place
indicated by the arrow) to measure that the drive belt tension is within the standard value.
Standard value: 197 - 371 N
3.If not within the standard value, replace the drive belt auto-tensioner (Refer to ).
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