Oil Cooler, Oil Pressure Gauge & Pressure Relief Valve

Oil Cooler. The purpose of oil cooler is to cool the lubricating oil in heavy duty engines, where the oil temperature becomes quite high. An oil cooler is known as heat exchanger. The oil may be cooled in it either by cold water from the radiator or the air stream. Water type oil cooler are more commonly  used  in  lubrication system because they act as reversible coolers. At the time of starting when the water is hotter than the oil, the oil is heated to provide complete circulation in the system. At high temperatures when the oil becomes hotter than water, the water cools the oil.

Oil Cooler

Location of Oil Cooler

Oil Pressure Gauge. An oil pressure gauge is mounted on the instrument panel of all motor vehicles, which are equipped with pressure lubrication system to show the oil pressure of the system to the driver. A pipe is taken from main oil gallery to gauge. The gauge shows variation of pressure in main oil gallery. The gauge is calibrated in lbs.per.sq.inch and thus driver can see the pressure of oil being delivered to the bearings at any time. A pressure warning light is also situated on dashboard and is connected to a pressure operated switch tapped into main oil gallery. When pressure reaches a predetermined figure, the switch is operated and extinguishes the light. Thus, driver  is warned only when the oil pressure is low  because as long as the pressure remains below predetermined figure the light will remain on.

Oil Pressure Gauge

Oil Pressure Warning Light

Pressure Relief Valve. The pressure relief valve is situated in the oil pump, main oil gallery or oil filter. It is often a ball or plunger and spring type valve, so that when the pressure exceeds the predetermined level, the ball is forced off its seating against the pressure of the spring. Excess oil is thus allowed to pass the ball, and return to the sump. The purpose of the pressure relief valve is to prevent the system becoming over pressurized, when speed is high or the oil is cold and thick.

Pressure Relief Valve