DETRIOT DIESEL 53
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
Under normal conditions, the pressure regulator valve should
Valve Opening Pressure (psi)
require very little attention. If sludge accumulates in the
lubrication system, the valve may not work freely, thereby
remaining open or failing to open at the normal operating
pressure. 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.
1. Remove the plug and washer from the engine lower front cover.
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.
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
side of the cover; then tighten the plug.
Fig. 1. Location of Current Oil Pressure
Regulator Valve--In Line Engine Shown
April, 1971 SEC. 4.1.1 Page 1