DETROIT DIESEL 53
LUBRICATING OIL PRESSURE REGULATOR
Stabilized lubricating oil pressure is maintained within
the engine at all speeds, regardless of oil temperature,
by a pressure regulator valve installed in the engine
lower front cover as shown in Fig. 1
The regulator assembly consists of a hollow piston type
valve, a spring, gasket and plug. The valve is located
in an oil gallery within the lower front cover and is held
tight against a counterbored valve seat by the valve
spring and plug.
When the oil pressure exceeds a
given value as shown in the following chart, the valve is
forced from its seat and the lubricating oil is by-passed
into the engine oil pan.
Fig. 1. Location of Former Oil Pressure Regulator Valve
-6V Engine Shown
Whenever the lubricating oil pump is removed for
inspection, the regulator valve and spring should also be
removed, thoroughly cleaned in fuel oil and inspected.
Under normal conditions, the pressure regulator valve
Remove Oil Pressure Regulator
should require very little attention.
accumulates in the lubrication system, the valve may
Remove the plug and washer from the engine
not work freely, thereby remaining open or failing to
lower front cover.
open at the normal operating pressure.
Withdraw the spring and the valve from the
Clean all of the regulator parts in fuel oil and dry them
with compressed air. Then inspect the parts for wear or
The regulator valve must move freely in the valve bore.
If the valve is scored and cannot be cleaned up with
crocus cloth, it must be replaced.
Replace a fractured or pitted spring.
Install Oil Pressure Regulator
Apply clean engine oil to the outer surface of the
valve and slide it into the opening in the engine lower
front cover (closed end first).
Install a new copper gasket on the plug.
While compressing the spring, start the plug in
the side of the cover; then tighten the plug.
1972 General Motors Corp.
SEC. 4.1.1 Page 1