SFN-20231018D_Relocate the oil pressure switch

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TICO Document #: SFN-20231018D (formerly TES-245)

Complaint: Possible oil feed hose failure due to chaffing, which connects the air compressor to the PSI engine

Cause: Tico installed an oil pressure switch inline with the oil feed hose to sense engine operation. The oil feed hose routing was altered, which created the issue.

Solution: Relocate the oil pressure switch on the air compressor to the oil cooler located on the rear of the PSI engine

Units Affected: 4506-4524, 4582, 4967-5006, 5009-5034, 5101-5126, 5143

Parts Required: FITTING, ADAPTER, 3/4" O-RING X 1/8" NPT FEMALE, STEEL 420393 (QTY) 1

Planned Labor: 15 minutes

Instructions:

  1. Park the vehicle on a flat surface, apply a parking brake, and chock wheels. If your company utilizes a “Lock Out, Tag Out” policy, you should employ it during this procedure.

  2. Tilt the cab to gain access to the engine. See Figure #2

    CAUTION: Be sure the cab safety latch is properly engaged.

  1. Move to the left-hand side of the truck and locate the engine air compressor. See Figure #3.

  1. Locate the oil pressure switch installed on the tee fitting. Remove the electric connections and take note of which spade connector goes to which terminal on the oil pressure switch. See Figure #4

  1. Remove the pressure switch from the tee fitting by turning it counterclockwise. Do not use oil switch body to loosen it. Set the oil pressure switch aside to be reinstalled later. See Figure #5.

  1. Remove the oil feed hose from the fittings on the air compressor. Be sure to temporarily secure the open hose connection upward so not to discharge oil into the environment. See Figure #6.

    Note: If the oil feed hose is showing signs of chaffing or leakage, it should be replaced.

  1. Remove the two fittings installed on the air compressor. Retain the adapter fitting. Discard the tee fitting (red arrow). See Figure #7.

  1. Re-install the adapter fitting into the air compressor. See Figure #8.

    CAUTION: When using sealant tape on the fitting connection threads, be sure that the tape does not overlap into the interior of the hose.

  1. Re-install the oil feed hose onto the air compressor at the adapter fitting. See Figure #9.

  • Tighten the oil feed hose to 22 ft-lbs of torque.

  • Use a torque paint stripe to indicate that the hose has been installed at the specified torque valve.

  1. Locate the engine oil cooler on the back of the engine. See Figure #10.

  1. Remove the oil port plug (red arrow) on the oil cooler. This fitting will no longer be used and can be discarded. See Figure #11.

  1. Install the 3/4“ O-ring port adapter fitting (Tico p/n: 420393) into the open oil cooler port. See Figure #12.

  2. The adapter fitting is to be tightened to 40 ft-lbs of torque.

  3. Use a torque paint stripe to indicate that the adapter fitting has been installed at the specified torque valve.

  1. Re-install the oil sensor into the adapter fitting on oil cooler. See Figure #13.

    CAUTION: Do not use a switch body to tighten. When using sealant tape on the switch’s threads, be sure that the tape does not plug the switch’s orifice.

  1. Re-install the electrical connections to the oil pressure sensor. See Figure #14. You may have to remove the existing zip ties, as shown in Figure #15, to properly route the harness to the oil pressure sensor.

  2. Re-install zip ties to ensure proper routing of the harness

  1. Remove “Lock Out, Tag Out” plaque.

  1. Return vehicle to service.