Drive Belt Tensioner: Testing and Inspection

AUTO-TENSIONER CHECK

OPERATION CHECK

1. Turn OFF the engine from the idle state then check to see that the drive belt is not protruding from the pulley width of the auto-tensioner.

2. Remove the drive belt. (Refer to Service and Repair).





3. Securely insert the spindle handle or ratchet handle with a 12.7 mm (1/2-inch) insertion angle into the jig hole of the auto tensioner. Turn the 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 auto-tensioner. (Refer to Service and Repair).
5. Install the drive belt. (Refer to Service and Repair).

FUNCTION CHECK

You can verify if the auto-tensioner is defective or not by checking the drive belt tension.

[When using special tool MB992080: Recommendation]

Required Special Tools:

- MB992080: Belt Tension Meter Set
- MB992081: Belt Tension Meter
- MB992082: Microphone Assembly

1. Check the drive belt tension. (Refer to [1][2]Drive Belt Tension Check and Adjustment).









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.

Measure the drive belt tension vibration frequency by the following procedures:
(1) Connect special tool MB992082 to special tool MB992081 of special tool MB992080.
(2) Press the "POWER" button to turn on the power supply.
(3) Press the numeral key of "1" and check that "No. 1" appears on the upper left of the display.
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.

(4) Press "Hz" button twice to change the display to the frequency display (Hz).
(5)

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.

Hold special tool MB992080 to the middle of the drive belt between the pulleys (at the place indicated by arrow), approximately 10 - 15 mm (0.4 - 0.59 inch) away from the rear surface of the belt so that it is perpendicular to the belt (within an angle of ± 15 degree).
(6) Press the "MEASURE" button.
(7) Gently tap the middle of the 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 belt is within the standard value.
Standard value: 120 - 154 Hz
NOTE:
To take the measurement repeatedly, fillip the belt again.

(8) Press and hold the "POWER" button to turn off the power supply.
3. If not within the standard value, replace the auto-tensioner. (Refer to Service and Repair).

[When using a tension gauge]

1. Check the drive belt tension. (Refer to [1][2]Drive Belt Tension Check and Adjustment).





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.

Use a belt tension gauge in the middle of the belt between the pulleys (at the place indicated by the arrow) to measure that the belt tension is within the standard value.
Standard value: 340 - 562 N (76 - 126 pounds)
3. If not within the standard value, replace the auto-tensioner. (Refer to Service and Repair).