ISC, ISCe, QSC8.3, ISL, ISLe3, ISLe4 and QSL9 Engines – 009-053   Belt Tensioner, Refrigerant Compressor, Automatic

Check the tensioner arm, pulley, and stops for cracks.

If cracks are found, the tensioner
must be replaced.

With the belt on, verify that neither of the tensioner arm stops are in contact with the spring casing stop.

If either stop is touching, the drive belt
must be replaced.

If the tensioner arm stops are still in contact with the spring case stop after replacing the belt, replace the tensioner.

Check the location of the drive belt on the belt tensioner pulley. The belt should be centered on, or close to the middle of, the pulley.

Misaligned belts, either too far forward or backward, can cause belt wear, belt roll-off failures, or increase uneven tensioner bushing wear.

WARNING  Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative (-) battery cable last.

• Disconnect the battery.
  Refer to Procedure 013-009 (Battery Cables and Connections) in Section 13 of the ISBe, ISB, and QSB (Common Rail Fuel System) Service Manual, Bulletin 4021271,
  or Procedure 013-009 (Battery Cables and Connections) in Section 13 of the ISC, ISCe, QSC8.3, ISL, ISLe3, ISLe4 and QSL9 Engines Troubleshooting and Repair Manual, Bulletin 4021418.
• Remove the belt guard, if equipped.
  Refer to Procedure 008-001 (Belt Guard) in Section 8 of the ISBe, ISB, and QSB (Common Rail Fuel System) Service Manual, Bulletin 4021271,
  or Procedure 008-001 (Belt Guard) in Section 8 of the ISC, ISCe, QSC8.3, ISL, ISLe3, ISLe4 and QSL9 Engines Troubleshooting and Repair Manual, Bulletin 4021418.
• Remove the drive belt.
  Refer to Procedure 009-052 (Drive Belt, Refrigerant Compressor) in Section 9.

Remove the capscrew and belt tensioner from the mounting location.

With the belt removed, verify the tensioner arm stop is in contact with the spring casing stop.

If these two are
not touching, the tensioner
must be replaced.

Measure the clearance between the tensioner spring casing and the tensioner arm to verify tensioner wear-out and uneven bearing wear.

If the clearance exceeds 3 mm [0.12 in] at any point, the tensioner
must be replaced as a complete assembly.

Tensioners usually show a larger clearance gap near the lower portion of the spring casing, resulting in the upper portion rubbing against the tensioner arm.
Always replace the belt when a tensioner is replaced.

1. Tensioner cap
2. Tensioner arm
3. Spring case
4. Tensioner pulley
5. Clearance gap.

Inspect the tensioner for evidence of the tensioner arm contacting the tensioner cap.

If there is evidence of the two areas making contact, the pivot tube bushing has failed and the tensioner
must be replaced.

Inspect the mating surface for debris. The tensioner can become misaligned if particles are trapped between the mating surfaces.

Install the belt tensioner and capscrew.

WARNING  Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative (-) battery cable last.

• Lift and hold the tensioner, use a 3/8-inch square drive.
• Install the drive belt and release the tensioner.
  Refer to Procedure 009-052 (Drive Belt, Refrigerant Compressor) in Section 9.
• Install the belt guard, if equipped.
  Refer to Procedure 008-001 (Belt Guard) in Section 8 of the ISBe, ISB, and QSB (Common Rail Fuel System) Service Manual, Bulletin 4021271,
  or Procedure 008-001 (Belt Guard) in Section 8 of the ISC, ISCe, QSC8.3, ISL, ISLe3, ISLe4 and QSL9 Engines Troubleshooting and Repair Manual, Bulletin 4021418.
• Connect the battery.
  Refer to Procedure 013-009 (Battery Cables and Connections) in Section 13 of the ISBe, ISB, and QSB (Common Rail Fuel System) Service Manual, Bulletin 4021271,
  or Procedure 013-009 (Battery Cables and Connections) in Section 13 of the ISC, ISCe, QSC8.3, ISL, ISLe3, ISLe4 and QSL9 Engines Troubleshooting and Repair Manual, Bulletin 4021418.