Oil Pressure Testing

What Is Viscosity?

• Viscosity is a fluids resistance to flow.• Low viscosity – Thin oil• High viscosity – Thick oil

What Are The Functions Of Oil?

• To cool• To lubricate• To seal• To dampen noise• It allows any worn particles to be returned to

sump

Manual Checks To Be Carried Out Before Testing

• Change the oil• Change the oil filter• Check the electrical connections on the oil

pressure switch

• It is very important that the oil and filter has been changed as this can affect your findings

Visual Checks To Be Carried Out Before Testing

• Check around the sump and bell housing for any signs of leakage

• Check front engine oil seal and pulley for any signs of leakage

• Check oil filter and filter housing for any signs of leakage

• Check fuel pump and engine components for tightness of bolts

• Dip engine for oil• Make sure there is sufficient diesel in tank for starting

Pumps – What Is The Function Of A Pump?

• The function of a pump is to generate flow in a system

Different Types Of Pumps

• Piston type• Gear type – most commonly used in

lubrication systems• Vane type• Roller type• Impeller type• Screw type

What Is Pump Displacement?

• Pump displacement is the amount of fluid that a pump can move per stroke

• Remember – Pressure results from a resistance to flow

Reasons For Abnormal Oil Pressure

• Low oil level in the sump• Oil worn out/broken down• Leaks• Worn bearings• Relief valve not seated properly• Wrong grade of oil• Worn or perished seals• If the oil is too thin this will result in low oil pressure• If the oil is too thick this will result in high oil pressure

Film of oil between surfaces (shaft & bearing)

Shell bearing

Bearing cap

Bearing housing

Oil feed

Oil clearance

Procedures To Be Followed To Carry Out The Test

• Remove oil pressure sender unit or the plug in the side of the engine block

• Connect up the gauge• Start up the engine• Bring the engine up to normal running

temperature/manufactures spec• Make a note of your findings• Compile a report

Manufacturers Specifications For The Lubrication System of Perkins Engine• Dip the engine for oil and check oil pressure evry

day or every 8 hours• Replace oil and oil filter every 500 hours or 12

months• Only use good quality oil with a grade of 15W40

which is suitable for irelands temperatures and climate

• According to the specifications of this engine the lubricating oil pressure at normal running temperature should be……

• 300kPa – 43lbf/in – 3.0kg/cm