LV07 lubrication issue 1

Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1Hệ thống bôi trơn làm mát LV07 vấn đề bôi trơn 1

Student Workbook

LV07 Lubrication Systems (1)

kap all covers 6/9/03 9:48 am Page 13

Student Workbook for Technical Certificates in

Light Vehicle Maintenance and Repair

MODULE LV07 LUBRICATION SYSTEMS (1)

Contents

Page ……… Page

Introduction 3 Oil pressure warning lamp 23

Periodic Maintenance: 4 Oil pressure - normal 24

Lubrication System: 9 Variable flow PCV valve 28

Introduction

Engine oil filler cap Engine oil

dipstick

Engine oil filler cap Engine oil

dipstick

The main function of a lubrication system is to form a film of oil between the working surfaces of the components to prevent damage by direct contact and

to reduce friction to a minimum

The oil’s function is to act as a seal and protect against corrosion It is a means of conducting heat away from the moving parts and to wash away any abrasive and corrosive deposits from the working surfaces

Periodic Maintenance

Checking the oil level

Oil consumption is influenced by many factors New engines reach their normal value at around 3,000 miles (5,000km) High speeds and heavy loads can influence the rate of engine oil consumption

The engine oil should be checked periodically when refuelling, or before long journeys commence

Dipstick removed

Actual oil level

Maximum level mark

Minimum level mark

Dipstick removed

Actual oil level

Maximum level mark

Minimum level mark

When checking the oil level, it is essential that the vehicle is on level ground and the ignition is switched off Allow the engine oil to drain into the sump from the engine (if the engine is cold allow a longer period of time)

Pull the dipstick out and wipe it with a clean, none-fluffy cloth Re-insert it completely and pull it out Examine the oil level, ensuring that if the oil is topped up, it does not exceed the max mark Use the recommended oil for the vehicle

When filling, wipe around the oil filler cap to ensure no dirt falls into the engine when the cap is removed Ensure the oil filler cap is tightened correctly after topping up

Oil deteriorates in use and consequently provides less protection to the

engine Therefore, the oil and filter must be changed at the manufacturer’s recommended intervals Oil contamination occurs as a result of dust, grit, water, as well as carbon and acids from combustion by-products Un-burnt fuel can leak past the pistons, while other contaminants are the result of

corrosion and loose metal particles caused by natural wear and tear

Changing the engine oil

When draining engine oil to replace with new, the engine must be warmed up and the drain plug removed Allow the engine to drain until all the oil has emptied into the container

Dispose of the waste oil through the authorised waste disposal facility Oil filters should be crushed to squeeze out the oil before disposal Check with the local authority about waste disposal regulations

Replace the drain plug, ensuring that a new washer, seal or gasket is used and tighten according to the manufacturer’s recommendations Do not over fill

Replacing the oil and filter

Special service tool

Oil filter

Special service tool

Oil filter

To remove the oil filter, slacken off the filter from the engine and use a

drainage pan to collect the oil

Cleaning the gasket seating Cleaning the gasket seating

Clean the surface of the filter bracket

Check that the rubber gasket is installed on the new filter and apply oil to the seal

Lightly screw the filter until resistance is felt, then tighten the filter an extra three quarters of a turn

Refill the engine with new oil and check the level

Start the engine and check for oil leaks visually and by touch

Progress check 1

Answer the following questions:

removal?

replaced if necessary?

placed on level ground?

Lubrication System

Oil in the sump Oil strainer

release valve

Oil in the sump Oil strainer

release valve

Sump

The sump forms the bottom half of the crankcase and acts as a reservoir for

the oil It must be of a sufficient capacity to provide an adequate supply of oil

for the engine The dipstick enters the sump to enable a check on the oil

level

Strainer

The gauze filter fitted to the pickup-tube filters larger particles of abrasive

deposits to prevent them circulating around the engine and clogging the main

filter, therefore shortening its life Its main function is to protect the oil pump

Oil pump

The oil pump circulates the oil in the system and is situated either in the sump below the level of the oil, or positioned above the oil level as shown above The pump drive may be taken from the camshaft (overhead rocker valve gear) and driven by a gear, or taken from the crankshaft and driven direct (overhead camshaft valve gear)

Oil filter

This is usually made from paper and is of the element type It is replaced after a mileage of between 6,000 and10, 000 miles, at the same time as the oil Check the manufacturer’s service guide

Pressure release valve

This is a spring-loaded ball or thimble, which sits on a seat preventing the flow

of oil until a preset oil pressure has been reached It is fitted into the main oil gallery or incorporated within the oil pump casing The pressure release valve

is responsible for maintaining the working pressure of the lubrication system When the oil pressure reaches a predetermined pressure, the valve lifts off its seat allowing all excess oil to flow back into the sump

Oil pressure switch

This switch operates the oil warning light to warn the driver of a failure in the lubrication system caused by loss of pressure The oil pressure switch is fitted in the main oil gallery

Oil pressure gauge

The oil pressure gauge is connected to the main oil gallery by a pipe Its purpose is to ensure that an oil pressure reading is conveyed to the driver

Section through the crankshaft showing oil ways

Section through the crankshaft showing oil ways

Oil ways drilled through the crankshaft webs supply oil to the big end bearings from the main bearings

Crankshaft pulley mount

Oil drillings

Oil drillings Flywheel

mounting flange

Rear main bearing

Crankshaft pulley mount

Oil drillings

Oil drillings Flywheel

mounting flange

Rear main bearing

A separate drilling up to the top of the engine supplies oil from the main

gallery to the valve gear, the surplus oil then falls down the engine into the sump to be circulated again

The connecting rods have a hole drilled through their length and provide pressure fed lubrication to the piston pin (gudgeon pin) The connecting rod is fed from the crankshaft big end bearings

This method directs a jet of oil onto the piston pin every time a hole in the big end bearing journal lines up with a hole in the connecting rod It also

lubricates the cylinder and piston by splash The pistons and cylinders are lubricated when oil is thrown up from the big end bearings by centrifugal force

Internal gear oil pump

Oil is drawn up through a strainer and a pickup tube when the engine rotates When the pressure rises above a predetermined level of about 4.0kg/cm² (56.9 psi), it overcomes the spring force of the pressure release valve, which opens allowing excess oil to return to the sump If a fault develops and the pressure release valve sticks open, the oil pressure will not be achieved and this could cause damage due to seizure of engine parts

If the pressure release valve sticks and remains closed, then the oil pressure will rise to an abnormally high pressure, which will cause oil to leak out of the engine A worn oil pump will cause the oil pressure to drop

This type of pump can be driven direct from the front of the crankshaft and does not require a separate drive gear Normally two flats on the middle gear drive the pump centre gear This meshes with the outer gear, which is

positioned off-centre

Rotation of the gears carries oil from the inlet to the outlet side, in the tooth spaces on both sides of the spacer Since the teeth mesh together, the oil cannot return As a result there is a build up of oil pressure Oil pumps that are submerged in the oil do not require priming but pumps fitted above the oil may give problems if the engine has been standing for a considerable length

of time, or if the pump has been assembled dry So, take care

Also, note that the inlet (suction) port is larger than the outlet This is to avoid

a condition known as ‘cavitation’ There is always adequate oil available and air locks are prevented

To avoid drain back into the sump, a non-return valve may be fitted between the strainer and the pump

Rotor type pump (Hobourn-Eaton oil pump)

This pump is very similar to the external gear type, it is driven by the camshaft and

is submerged

in the oil

This pump is very similar to the external gear type, it is driven by the camshaft and

Gear type pump

The gear type pump involves two meshing gears, which draw oil up from the sump into the spaces between the gears When the gear teeth come

together, they squeeze out the oil under pressure to the engine The oil

travels around the outside edge of the gears For many years the gear type pump was almost universal, it is still in common use

Eccentric vane type oil pump

Inlet

Casing

Spring loaded vanes

Slotted vane Driven from camshaft

Inlet

Casing

Spring loaded vanes

Slotted vane Driven from camshaft

The rotor is mounted on a shaft eccentric to the casing bore

In the first illustration, the vane is spring loaded and the outer edges are kept

in contact with the casing by a spring Oil is carried around from the inlet to the outlet

In the second illustration, a spring is not used there are two cut away piece vanes fitted in a slot at right angles to each other The casing is so shaped that each vane remains in contact with the casing at both ends in all positions

one-Pressure release valve

To control the amount of oil flowing in the lubrication system, it is necessary to regulate the pressure This is achieved by using a pressure release valve The oil pressure release valve is often fitted integrally in the pump body, although it can be a separate item

Filters

The purpose of filters in the lubrication system is to remove abrasive particles from the oil, which would cause an increase in wear and eventual damage to the engine bearings

Filters are replaceable and contain about 4 metres of resin-impregnated

paper This is shaped to give a very large surface area to the oil passing through it

When the filter element is fitted with a by-pass valve and the element

becomes blocked by impurities, the differential in pressure between the inlet and the discharge (outlet) side of the filter rises above a pre-determined level 1kg/cm² or 14 psi The by-pass valve opens and allows oil to by-pass the filter element Therefore unfiltered oil passes to the engine parts to prevent seizure

The small pores of the paper trap the small particles of around 25 microns There are two main types of filter used in motor vehicles

These are:

• full-flow

• by-pass

Full flow filter

Sump Strainer

Only some of the oil is filtered, the oil flows directly to the bearings The pass filter is usually finer and will filter much finer particles than the full-flow type Filtering is done as the oil returns to the sump

by-Progress check 2

Answer the following questions:

recommended that the _ should be changed at the same time

lubricate the underside piston

gear wheels

Oil cooler

Heat is the enemy of oil and engines While the cooling system cools the cylinder block and cylinder head, the rest of the engine’s internal components rely on engine oil for cooling, transferring heat, lubricating and cleaning

Engine oil becomes quite hot during service as it removes heat from engine parts Normally, the only cooling of oil is from the air stream passing over the engine sump

The cooling system is doing its job if it is keeping the engine temperature under control, so that the oil doesn’t have too much to contend with Oil loses heat as it travels through the filter and the engine is radiating heat

continuously For all of these reasons, it is unusual for engine oil to overheat However, there are some situations when oil cooling is necessary, such as with high-powered engines, or engines that carry heavy loads Almost all air-cooled engines have oil coolers

There are several types of oil coolers, but the two most commonly used in motor vehicles are fitted between the engine block and the oil filter Water circulates around the oil and cools it

Another type is fitted in the water-cooling radiator and borrows a small section

of the cooling area within the radiator It is cooled by air ‘ram’ action through the radiator

Some oil cooling systems use a separate radiator, which is fitted in the air stream at the front of the vehicle Oil coolers may have a thermostat fitted to ensure that the oil is not over cooled and that the oil is prevented from

circulating through the cooler when the engine is cold

Air cooled oil cooler

Oil filter

Pressure release valve

Oil cooler Oil filter

Pressure release valve

Oil cooler Oil filter

Pressure release valve

Oil cooler

Part of the oil flows from the oil pump to the air-cooled oil cooler, then it

returns to the sump

When the engine speed is low and the pressure falls to approximately

3.0kg/cm² the relief valve for the oil cooler closes and oil is therefore

prevented from flowing to through the oil cooler

To main oil gallery

To oil cooler

From pump

Release valve

To main oil gallery

To oil cooler

From pump

Release valve

When the oil pressure rises as engine speed rises, the release valve opens and oil flows through the cooler and back to the sump

Temperature of engine oil should not rise above 100°C At 125°C, the oil begins to lose its lubrication properties

Water cooled oil cooler

Oil filter Oil cooler with

release valve Engine coolant

Engine coolant

To main oil gallery

Engine

release valve

Oil filter Oil cooler with

release valve

Engine coolant

Oil filter Oil cooler with

release valve Engine coolant

Engine coolant

To main oil gallery

Engine

release valve

Due to increasing compactness within engine compartments, it has become difficult in some cases to fit an air-cooled oil cooler This is because the space required is no longer available on modern vehicles It has become more common to fit a water- cooled oil cooler

In this system, all the oil flows from the pump to the oil cooler, where it is cooled After being cooled, the oil flows from the cooler to lubricate the

engine parts

A pressure release valve is used to prevent damage to the oil cooler due to increased oil pressure when the engine is cold, which increases thickness of the oil at low temperatures

When the differential between the inlet side of the cooler increase to more than 1.5kg/cm on the outlet side, the pressure release valve opens and oil flows from the oil pump, by-passing the oil cooler and continues to lubricate the engine

Oil pressure warning lamp

The oil pressure switch is mounted in the cylinder block and is usually directly monitoring the oil pressure in the oil gallery

Low pressure

The points inside the pressure switch are closed when the engine is stopped

or when the oil pressure falls below its predetermined pressure usually this is about 0.2kg/cm², this causes the oil warning lamp to light