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.
Whenever the lubricating oil pump is removed for
inspection, the regulator valve and spring should also
be removed, thoroughly cleaned in fuel oil and
Under normal conditions, the pressure regulator valve
should require very little attention. If sludge
Remove Oil Pressure Regulator
accumulates in the lubrication system, the valve may
not work freely, thereby remaining open or failing to
1. Remove the plug and washer from the engine lower
open at the normal operating pressure.
2. Withdraw the spring and the valve from the cover.
Clean all of the regulator parts in fuel oil and dry
them with compressed air. Then inspect the parts for
wear or damage.
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
1. 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).
2. Install a new copper gasket on the plug.
3. While compressing the spring, start the plug in the
Fig. 1 - Location of Current Oil Pressure
Regulator Valve -- In-line Engine Shown
side of the cover; then tighten the plug.
April, 1971 SEC. 4.1.1 Page 1