N14 Base Engine Troubleshooting and Repair Manual – 007-021   Lubricating Oil High Pressure Relief Valve

The high pressure relief valve (1) is held in the closed position by spring force (2). The valve remains in the closed position until the oil pressure exceeds 1724 kPa [250 psi] in the lubricating oil pump.

When the oil pressure exceeds 1724 kPa [250 psi] in the lubricating oil pump, for instance during cold start-up, the oil pressure in the pump overcomes the relief valve spring force.

This allows the excess oil to return to the oil pan, preventing possible damage to the lubricating system components.

Measure the installed depth of the high pressure relief valve retainer plug.

If the plug depth is less than 6.48 mm [0.255-inch], use DFC pressure relief valve fixture, Part No. 3376011, to install it to the correct depth of 6.48 mm to 6.98 mm [0.255-inch to 0.275-inch].

NOTE: If the plug depth is within specifications and the engine oil pressure is out of specifications, check the high pressure relief valve and the lubricating oil pressure regulator. Refer to Procedures

007-021-007 and

007-029-007, respectively.

Remove the lubricating oil pump. Refer to Procedure

007-031-002.

Remove the lubricating oil pump cover.

Remove all gasket material from the lubricating oil pump body and cover.

Clean the high pressure relief valve assembly.

WARNING  Carefully remove the retainer plug (1). The high pressure relief valve spring (4) is under compression. Personal injury can result. Wear face and eye protection.

Use the light duty puller kit, Part No. 3375784, or its equivalent to remove the retainer plug (1).

Remove the valve disc (2), the washer (3), and the high pressure relief valve spring (4).

Inspect the parts for damage.

Use valve spring tester, Part No. 3375182, to measure the high pressure relief valve spring force.

Compress the spring to a height of 29.0 mm [1.145 inch].

NOTE: The force required to compress the spring

must be:

• Minimum 260 Newtons [59 lb]
• Maximum 320 Newtons [72 lb]

Measure the high pressure relief valve seat depth in the lubricating oil pump. The maximum depth is 46.73 mm [1.840 inch].

Install the locating plate, Part No. 3376013, (in DFC pressure valve fixture, Part No. 3376011), onto the lubricating oil pump body. Use two 5/16-18 inch UNC x 1-1/4 inch capscrews. Do

not tighten the capscrews at this time.

Install the large diameter of the valve mandrel, Part No. 3376012, (in DFC pressure valve fixture, Part No. 3376011), through the locating plate into the pressure limit valve bore in the pump body.

Tighten the capscrews, and remove the mandrel.

Install the spring (4), the washer (3), the valve disc (2), and the retainer plug (1) into the bore in the locating plate.

Make sure the prongs on the disc are down (toward the washer) and the cup side of the retainer plug is up (toward the mandrel).

Install the small end of the valve mandrel, Part No. 3376012, into the bore in the locating plate.

Press the mandrel with an arbor press until the large diameter of the mandrel is against the locating plate.

Install a new gasket and the cover to the pump body.

Install the capscrews and the washers and tighten.

Turn the gear to make sure it rotates freely.

Install the lubricating oil pump. Refer to Procedure

007-031-026.

Confirm that the oil level in the oil pan is to the full mark.

Operate the engine until the water temperature reaches 82°C [180°F]. Check the oil pressure, and check for oil leaks.