Section 3.3
Oil Pressure Regulator Valve

An oil pressure regulator valve maintains stable lubricating oil pressure within the engine, regardless of the oil temperature. Oil leaving the pump under pressure passes into the pressure relief valve body. The valve is installed in the end of a vertically drilled passage in the cylinder block, located on the oil cooler (right) side of the block, that connects with the main cylinder block oil gallery. See Figure "Oil Pressure Regulator Valve Mounting" .‪

Figure 1. Oil Pressure Regulator Valve Mounting

The oil pressure regulator valve consists of a valve body, a hollow piston-type valve; a spring, a spring seat; and a pin to retain the valve assembly within the valve body. See Figure "Oil Pressure Regulator Valve Parts and Relief Valve Details" .‪

Figure 2. Oil Pressure Regulator Valve Parts and Relief Valve Details

The valve is held on its seat by the spring, which is compressed by the pin in back of the spring seat. The entire assembly is bolted to the lower flange of the cylinder block and sealed against leaks by a gasket between the block and valve body. When conditions are such that the oil pressure at the valve exceeds 310 kPa (45 psi), the valve begins to be forced from its seat and oil from the engine gallery is bypassed to the engine oil pan. Thus, stable lubricating oil pressure is maintained at all times.‪

Section 3.3.1
Repair or Replacement of Oil Pressure Regulator Valve

To determine if repair is possible or replacement is necessary, perform the following procedure. See Figure "Flowchart for Repair or Replacement of Oil Pressure Regulator Valve" .‪

Figure 3. Flowchart for Repair or Replacement of Oil Pressure Regulator Valve

Section 3.3.2
Removal of Oil Pressure Regulator Valve

Remove the oil pressure regulator valve as follows:‪

1. Drain the lubricating oil and remove the oil pan. Refer to "3.11.2 Removal of Oil Pan" .
2. Remove the two regulator-to-cylinder block attaching bolts and washers.
3. Tap the regulator body lightly to loosen it from the gasket and cylinder block.
4. Remove the oil pressure regulator valve and gasket.

Section 3.3.3
Disassembly of Oil Pressure Regulator Valve

Disassemble the oil pressure regulator valve as follows:‪

EYE INJURY ‪
To avoid injury from flying debris when using compressed air, wear adequate eye protection (face shield or safety goggles) and do not exceed 276 kPa (40 psi) air pressure.‪

1. Clamp the regulator in the soft jaws of a bench vise and remove the spring seat retaining pin from the regulator body.
2. Remove the spring seat, spring and valve from the regulator body.

Section 3.3.3.1
Inspection of Oil Pressure Regulator Valve

Inspect the oil pressure regulator valve as follows:‪

1. Clean all of the oil pressure regulator valve components in fuel oil.

   EYE INJURY ‪
   To avoid injury from flying debris when using compressed air, wear adequate eye protection (face shield or safety goggles) and do not exceed 276 kPa (40 psi) air pressure.‪

2. Dry the components with compressed air.
3. Inspect the oil pressure regulator valve for movement. Check to see if the oil pressure regulator valve moves freely in the valve body.
   1. If oil pressure regulator valve binds, replace it with a new part.
   2. If oil pressure regulator valve does not bind, reuse part.
4. Inspect the components for wear or damage. Check to see if valve or the valve body are scored.
   1. If the valve or valve body parts cannot be cleaned up with a fine emery cloth, replace with new parts.
   2. If the valve or valve body parts can be cleaned up with a fine emery cloth, reuse parts.
5. Inspect spring for pitting or fractures.
   1. If spring is damaged, replace it.
   2. If spring is not damaged, reuse the component.

Section 3.3.4
Assembly of Oil Pressure Regulator Valve

Assemble the oil pressure regulator valve as follows:‪

1. Apply clean engine oil to the outer face of the valve. See Figure "Comparison of Pressure Regulator and Relief Valve Assemblies" .
2. Slide valve into the regulator body, closed end first. See Figure "Comparison of Pressure Regulator and Relief Valve Assemblies" .
3. Insert the spring in the valve and install the spring seat.
4. While compressing the spring, install the retaining pin behind the spring seat.
5. Press the pin flush to 0.254 mm (0.010 in.) below the surface of the valve body.

   Note: The valve body has two retaining pin holes. See Figure "Comparison of Pressure Regulator and Relief Valve Assemblies" . Install the pin in the outermost hole for the regulator valve. The retaining pin must be positioned correctly so the proper valve opening pressure will be obtained. Although the same casting is used for both the pressure regulator and relief valves, the regulator valve has a slightly larger opening machined into the side. See Figure "Comparison of Pressure Regulator and Relief Valve Assemblies" .

   

   Figure 4. Comparison of Pressure Regulator and Relief Valve Assemblies

Section 3.3.5
Installation of Oil Pressure Regulator Valve

Install the oil pressure regulator valve as follows:‪

1. Remove all traces of old gasket material from the mating surfaces of the regulator body and the cylinder block.
2. Secure the oil pressure regulator valve assembly to the cylinder block with two bolts. Torque the bolts to 30-38 N·m (22-28 lb·ft).
3. Refer to "12.3 Running" for verification of proper oil pressure regulator installation.