Paccar PX-9, Operator'S Manual

Page: 71 / 97

• Frayed or exposed belt threads
• Signs of animal activity - gnaw
marks
• Belt to pulley misalignment
• Oil, grease, or coolant
contamination
• Foreign matter pinched
between the belt and pulleys or
signs of this condition
previously like debris in belt or
pulley grooves
2. Listen to the engine on start up or
acceleration for any squealing. This
is an indication that a belt may be
slipping.
If you find signs of premature belt failure,
identify, and address the underlying
problem as soon as possible and replace
the belt making sure that it is installed,
aligned, and that the tensioner is working,
properly (belt should be taut).
Fan Belt Tensioner (If So Equipped)
Perform this maintenance procedure at the
mileage or engine hours specified in the
Preventative Maintenance Schedule.
1. Check and correct fan belt
tensioner.
• Mounting bolt torque
• Tensioner maintains proper belt
tension
Fan Belt Removal - If so equipped
Perform this maintenance procedure at the
mileage or engine hours specified in the
Preventative Maintenance Schedule.
1. Disconnect the electrical ground
wire from the battery.
2. Reach between the fan blades and
remove the fan blade mounting
bolts using a 9/16 in. socket.
Remove the fan and store it
temporarily where it cannot be
damaged.
3. Place a flex-bar with a 15 mm
socket on the fastener securing the
automatic belt tensioner's roller, as
shown in the image.
4. Rotate the flex-bar as shown in the
diagram to relieve belt tension.
5. With the belt tensioner pressure
relieved, remove the poly V-belt
from the pulleys.
• The tensioner can be
temporarily blocked with a
0.16-0.2 in. (4-5 mm) thick pin
(bore). This facilitates removal
and installation of the poly V-
belt.
6. After removing the belt, carefully
allow the belt tensioner to spring
back to the stop (if it had not been
temporarily blocked).
7. Inspect the pulleys for damage,
rust, and grease deposits. Clean or
replace as necessary.
Fan Belt Installation - If so
equipped
Follow the steps below to install the fan
belt:
1. Place a new poly V-belt over the
pulleys, making certain the belt
falls into all the belt pulley grooves.
This will ensure proper alignment.
NOTE
When installing the belts DO NOT
wrap belt around the tensioner until af-
ter the belt has been wrapped around
all other pulleys and idlers.
2. After installing the belt, carefully
allow the belt tensioner to spring
back to its normal position. If the
tensioned had been temporarily
blocked, relieve tensioner pressure
enough to remove the locking pin,
ENGINE MAINTENANCE - Maintenance Procedures
68 Y53-1185-1J1 (10/21)
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