CHAPTER 45 Engine Lubrication.

CHAPTER 45 Engine Lubrication

Introduction Machinery relies on lubrication.
Keeps parts from wearing out quickly Lubricating oil is processed from crude oil. Heavily processed with many additives Moving engine parts need lubricating oil. Through lubrication system

Oil (1 of 24) Engine oil originates as crude oil.
Additives make it useful. Prevent acid formation Reduce oxidation Maintain correct viscosity

Oil (2 of 24) Functions of lubricating oil Lubricates Cushions Cools
Cleans Seals

Oil (3 of 24) Lubrication Reduces friction Engine can seize.
Protects against corrosion Prevents metal-to-metal contact

Oil (4 of 24) Lubrication affects engine life span.
Points of extreme loading especially need lubrication. Helps cushion shock loads Lubrication cools the engine. Oil collects heat and returns to sump. Heat is picked up by air. Heavy-duty/high-performance vehicles may have cooling fin or separate oil cooler.

Oil (5 of 24) Lubrication cleans the engine. Lubrication seals.
Additives collect particles and bring to sump. Removed when changed Lubrication seals. Seals piston rings to cylinder walls.

Oil (6 of 24) Lubrication protects against corrosion. Acids form from:
Accumulation of by-products and moisture Chemical reaction from blow-by gases Moisture from the cooling process Anticorrosion additives coat and protect engine surfaces.

Oil (7 of 24) Oil viscosity is an important factor.
Viscosity measures how easily a liquid flows. Lubricating oil must be thin enough to circulate easily. Not thin enough to be squeezed out Clearances between parts have decreased. Need thinner oils Thinner oil flows more easily, increasing fuel economy.

Oil (8 of 24) Oil additives include: Extreme pressure additives
Coats parts so oil resists being forced under heavy load Oxidation inhibitors Stops combination of hot oil and oxygen, which would clog galleries and passages Corrosion inhibitors Stops acid formation, preventing corrosion

Oil (9 of 24) Oil additives (cont’d) Anti-foaming agents
Reduce oil churning effect and minimize foaming Foaming reduces lubrication quality and causes oxidation and increased friction. Detergents Reduce carbon deposits Dispersants Prevent particles from blocking system

Oil (10 of 24) Oil additives (cont’d) Pour point depressants
Prevent wax particle formation in cold Wax crystals result in gelling. Viscosity index improver Reduces viscosity change during temperature change

Oil (11 of 24) Oil rating standards
American Petroleum Institute (API) rates engine oil. Two-part classification Service class S for spark ignition engine C for compression ignition engine S rating cannot be used in compression ignition engine unless also C rated, vice versa. Service standard

Oil (12 of 24) API symbol Back of bottle
Top has service class and standard. Center has SAE viscosity rating. Possible energy saving designation

Oil (13 of 24) American Society of Automotive Engineers (SAE) rates engine oil viscosity. Producers must meet SAE rating. Higher number means higher viscosity. Low viscosity oils are tested at low temperatures. High viscosity oils are tested at high temperatures. Modern oils are multiviscosity. Better lubrication Flow easily during cold start-up and do not thin out too much

Oil (14 of 24) International Lubricant Standardization and Approval Committee (ILSAC) Creates engine oil specifications with API Requires engine oil to provide better fuel economy than base lubricant Issues sequentially increasing standards Displays API starburst symbol

Oil (15 of 24) Association des Constructeurs Européens d’Automobiles (ACEA) Soot thickening Water Sludge Piston deposits Classifies European engine oil Oxidative thickening Fuel economy Much more stringent than API and ILSAC After-treatment compatibility Must score high on:

Oil (16 of 24) Japanese Automotive Standards Organization (JASO)
Sets standards for motorcycle engines and Japanese automotive diesel engines Four-stroke motorcycle: JASO T 903:2011 Two-stroke motorcycle: JASO M 34:2003 Automotive diesel: JASO M355:2008

Oil (17 of 24) Manufacturers set their own standards.
To keep up with their design changes Understand oil requirements for each vehicle you work on. Wrong oil can result in severe damage. Wrong oil can void warranty.

Oil (18 of 24) API classifications Group 1
Simple distillation of crude oil Most commercial products Group 2 Refined with hydrogen (hydro-cracking) Higher performance characteristics like synthetic

Oil (19 of 24) API classifications (cont’d) Group 3
Produced same as group 2, but more heavily cracked High viscosity index More higher performance characteristics Group 4 All of full synthetic PAO group Group 5 All other synthetic oils

Oil (20 of 24) Three types of oil Conventional Synthetic
Synthetic blend

Oil (21 of 24) Conventional oil Processed from crude oil
Refining removes impurities. Wax Broken down into mineral and combined with additives Vasily Smirnov/ShutterStock, Inc.

Oil (22 of 24) Synthetic oil Two categories of synthetic oil
Type 3: not true synthetic Type 4: true synthetic More costly because highly refined or made in lab Based on man-made hydrocarbons (PAO) Very few on market are full PAOs.

Oil (23 of 24) Advantages of synthetic lubricants
Better protection against engine wear Operate at higher temperatures Fewer impurities, including wax May last longer, which is good for environment Chemically more stable Better low temperature viscosity allowing quicker circulation during low-temp start-ups Thinner, allowing for closer tolerances

Oil (24 of 24) Synthetic blends
Some benefits of true synthetics and more cost effective Mix of conventional high-quality oil and full synthetic Fewer benefits than synthetic, more than conventional Recommended by some manufacturers due to better protection and performance

Lubrication Systems (1 of 31)
Keep engine components lubricated. Ensures engine runs cooler, produces max power, gets max fuel efficiency, lasts longer Components work together to deliver oil to correct locations.

Components of lubrication system: Oil sump Oil pump strainer Oil pump and filter Pressure regulator Oil galleries Low pressure warning system

Path of oil Stored in oil sump Drawn through oil pump strainer, removing dirt From filter to galleries Oil pumped to crankshaft main bearings travels through oil-ways to connecting rods. Oil may be splashed from connecting rods onto cylinder walls. Circulation assists with internal cooling.

Oil pan is at bottom of engine. Holds entire volume of oil Lowest point is oil sump. Oil pump strainer location Deep point prevents oil shortage.

Oil pan Sealed to engine with silicone or gasket Sump has drain plug.

Oil sump systems can be wet or dry. Wet sumps For most production vehicles due to low cost Oil kept in sump for continuous use Part of oil pan bolted to engine bottom Reservoir for lubricating oil Shaped so oil returns to deepest section Oil pickup and tube strainer in deep section to stay submerged

Dry sumps For high-performance applications Shallower oil pan than wet sump, allowing engine to sit lower Oil not stored under engine in oil pan Oil collection pan on dry sump replaces oil pan. Collects oil after circulation directing it to pickup strainer on scavenge pump Then moves to oil reservoir, then to engine Sump does not need dipstick.

High-performance vehicles may contain a windage tray. Pan located close to crankshaft to prevent oil churning

Baffles: flat pieces of steel placed around oil pump pickup to prevent oil surge During cornering, braking, accelerating Used on cars with strong g-forces

Pickup tube Located between oil sump and oil pump Flat cup and wire mesh strainer immersed in oil Draws oil from oil sump by oil pump suction and atmospheric pressure Strainer stops large particles. Leads into oil pump on low-pressure side, fitting tightly Engine would not receive oil if it fell out.

Oil pump moves oil from one side to other. Most are positive type displacement. Move given amount of oil from inlet to outlet each revolution More oil is pumped, the faster the pump turns.

Oil pressure determined by: Size of the leaks in the system Clearance Amount of oil flowing in the system Low oil pressure due to: Excessive engine leaks Worn-out oil pump Oil too thin

Types of oil pumps: Rotor type Crescent pump Geared oil pump

Rotor type Inner rotor drives outer one. Volume between them increases as they turn. Lower volume increases pressure at pump inlet. Outside pressure forces oil into pump and fills spaces between lobes. Oil squeezes through outlet as inner rotor lobes move into outer rotor spaces.

Crescent pump Usually mounted on cylinder block front straddling crankshaft front Inner gear is driven by crankshaft directly. External toothed gear meshes with inner one. Pressure falls due to increasing volume between teeth. Resulting vacuum pushes oil into pump. Oil is carried between gears and crescent until discharged to outlet port.

Geared oil pump Driving gear meshes with second gear. Teeth separate as they turn, creating low-pressure area. Outside pressure forces oil into inlet, filling spaces between teeth. Gears carry oil around chamber while rotating. Mashing teeth force oil from outlet to oil gallery and toward filter.

Oil pressure relief valve Prevents development of excess pressure Like a controlled leak, releasing just enough oil to maintain preset maximum relief pressure Spring calibrated to specific pressure Valve slides open when pressure is reached.

Oil filtering systems Full flow Most common Designed to filter all oil before delivery Bypass More common in diesel engines Used with full-flow filter

Oil filtering systems (cont’d) Use pleated filtering paper as medium Oil flows through paper. Particles down to 30 microns Paper clogs. Change at intervals.

Common oil filter types: Spin on (most common) One-piece filter assembly inside crimped housing Spins off Square-cute rubber O-ring Cartridge

Cartridge-style oil filters Use metal or plastic housing and replaceable filter cartridge Held together by threaded center bolt or screw-on housing Center bolt: Sealing washer between bolt and housing prevents oil leak. Must be disassembled, housing cleaned, paper filter/O-rings/seals replaced

Most filters on diesel engines are larger, and some diesel engines have two oil filters. Produce more carbon particles Full-flow element traps larger particles. Bypass collects sludge and carbon soot. Filters some oil by tapping line into oil gallery Returns to oil sump after filtering If bypass clogs, oil flow is not affected.

Connecting rods contain oil spurt holes to receive oil. Oil galleries feed oil to the cylinder head. Lubricates valve train

Oil indicators are a warning system for drivers. Indicates low oil pressure

Pressure sensor threaded into gallery sends low oil pressure warning message. Also known as a sending unit If part of warning lamp system, made of spring-loaded diaphragm and set of switch contacts If oil pressure drops below spring pressure, with running engine, light will come on.

Sending unit usually uses variable resistor if part of oil pressure gauge system. Moved by oil pressure moving diaphragm against spring pressure Changes resistance of variable resistor Current flow changes and gauge reads higher. Some factory-installed gauges include a warning light. Drivers may not notice when gauge reading falls.

Sending units part of driver information system can be: Switch type Variable resistance type Usually includes low oil level monitoring sensor or oil temperature monitor Check manufacturers’ information.

Oil coolers cool engine oil. Types of oil cooler Oil-to-water Transfers heat from oil to coolant from cooling system Circulating coolant removes heat. Oil-to-air Uses air passing across its fins to cool oil On most vehicles with tow packages

Oil-to-water cooler and oil filter may be on same mounting. Oil-to-air coolers are mounted on airstream at front of vehicle.

Oil analysis can determine wear of engine parts. Small tube is slipped down oil dipstick to oil pan sump. Vacuum device hooked to tube pulls sample. Oil sample is sent to lab for analysis. Reports can determine oil condition too. Technicians check for metal in the oil with a paper towel.

Oil monitoring systems indicate when oil needs changing. Systems are simple or sophisticated. Some only keep track of mileage. Some analyze oil conductivity through sensor. Oil-life monitor calculates expected life of the oil and displays it as a percentage. Uses data from several sensors Changes drastically depending on conditions

Types of Lubrication Methods (1 of 8)
Modern engines use pressure, or force-feed, systems. Oil is forced through engine under pressure.

Wet sump Oil pump collects oil through pickup tube and strainer and forces it through filter. Flows through galleries in engine block Feeds to crankshaft bearings, then to connecting rods Also moves onto camshaft bearings and valve mechanism Falls back to sump to cool after circulation

Dry sump Parts and lubrication method same as wet Oil falls to bottom of engine into oil collection pan. Scavenge pump pumps it to oil tank to store until normal oil pump collects and pumps it normally. Engine can be mounted lower. Vehicle has much lower center of gravity. Tank can be positioned away from engine for best cooling. Holds more oil

Diesel engine lubrication is similar to gasoline engines. More stress in diesel engines Operate at higher internal temperatures Higher compression pressures Fuel produces more heat when ignited. Parts must be heavier due to extra stress. Oil has to handle higher shear forces. Different range of properties and classification Oil-to-water cooler is common.

Splash lubrication method Oil thrown around, getting into spaces For lubricating cylinder walls, pistons, wrist pin, valve guides, timing chain Oil from pressure-fed parts

Most four-stroke gasoline engines use only splash lubrication. On horizontal-crankshaft engines, oil may be pulled via a dipper. Oil slinger is used on most small-vertical crankshaft engines. Slings oil upward with centrifugal force Runs half-submerged in oil and driven by crankshaft or camshaft

Most two-stroke engines use specified gasoline-oil mixture for lubrication. Two-stroke oil and engine oil not substitutes Manufacturer-specified mixture Air/oil/fuel mixture passes through sealed crankcase to combustion chamber. Fuel evaporates leaving oil behind to lubricate. Crankshaft and connecting rod bearings are typically ball and roller types. Require minimum lubrication

Oil injection system Oil pump delivers oil to the engine to be mixed with fuel to lubricate parts. Designed to deliver correct amount of oil Oil pump sprayer may get clogged.

Maintenance and Repair (1 of 10)
Repair tools Oil filter wrenches Wrenches and socket set Mirror and light Socket to remove oil pressure switches and sensors DVOM

Check engine oil regularly. Possible engine damage if oil drops too low Oil leak Engine consumes oil by burning it. Due to: worn piston rings, worn valve guides, malfunction within PVC system Put vehicle on level surface and turn engine off. Wipe off dipstick and reinsert fully. Hold dipstick horizontally to read. Check service manual.

Oil-life monitor is best guide for when to change oil. If no monitor, check oil change sticker or ask customer. Milky gray oil on dipstick = water in the oil. Could indicate a serious problem in engine

Engine operation conditions also influence oil’s condition. Problems can ruin engine quickly due to inadequate lubrication. Do not forget to reinstall filler cap after topping off.

Drain the engine oil. If oil/filter changed or oil pan removed Necessary after certain time/mileage interval To remove dirt and particulates Removing contaminated oil makes engine last longer. Always check manufacturers’ intervals. Remember normal and severe use have different intervals.

Take precautions when changing the oil. Wear gloves. Hot oil Locate correct drain plug. Do not mistake plug on transmission/transaxle. Consider path of the oil. Hot oil sprays sideways Don’t overtighten drain plug gasket. Replace non-silicone gaskets each time.

Replacing oil filters Oil filters catch particles and let oil flow through. From carbon from combustion process that leaks past piston rings Small metal flakes result from normal engine wear. Change at manufacturer’s recommended mileage.

Use caution when changing a spin-on filter. Do not use an oil filter wrench for installation. Must be installed by hand Do not double-gasket the O-ring. Putting the new O-ring over the old one Lubricate the O-ring. Allows it to spin Finger-start the filter when reinstalling. Avoids cross-threading

Cartridge filters are increasing in popularity due to ease of oil disposal. Changing a cartridge filter Only replace paper filter cartridge and O-rings. Consult vehicle service information to locate. Be careful when tightening. Clean the filter housing before reinstallation.

Refill engine oil. Refill when performing oil and filter change. Check vehicle service information for amount and grade of oil. Start engine to build oil pressure and fill oil filter after refilling. Then shut off to check for leaks and dipstick level.

Diagnosis (1 of 7) Common issues Failure to change the oil
Most important for customers Leads to sludge formation preventing lubrication Very expensive to rebuild or buy new engine Oil leaks Leaking from seals or oil pressure sending unit Look over engine and mating surfaces closely.

Diagnosis (2 of 7) Common issues (cont’d) Noise
From low oil pressure creating valve train noise Worn bearings or worn oil pump Low oil level or too thin oil Leaked or burnt-off oil Too much/too little oil Whipped into foam by crankshaft, causing leaks Drag from crankshaft causes loss of power and more fuel consumption. Oil pump starves engine of oil due to foam.

Diagnosis (3 of 7) Diagnostic tools:
Oil pressure gauge to measure oil pressure Mechanic’s stethoscope to check for noises DVOM to test electrical circuits of sensors/gauges Fluorescent dye and black light to find leaks Oil pressure sending unit sockets to remove oil pressure sending units Resistance substitution box to diagnose gauge problems

Diagnosis (4 of 7) Test the oil pressure.
Test if low oil pressure is suspected. You will need to verify dash reading. Check noisy engine for low pressure. Engine damage due to no or low oil Use a quality oil pressure gauge. Installed by oil pressure sensor If oil pressure lower than specifications, refer to service information. If oil pressure higher than specifications, suspect sticking oil pressure regulator.

Diagnosis (5 of 7) Inspect the oil sensors. Variable resistance
Gauge reads different amounts depending on resistance. Fixed resistance In line with spring-loaded switch When oil pressure is above spring pressure, switch closes and gauge indicates midpoint pressure. Substitute specified resistance in place of sensor and observing oil pressure gauge to test. Refer to vehicle service information.

Diagnosis (6 of 7) Inspect the engine assembly for leaks.
Fluid leaks are common. Seals and gaskets leak over time. Use color, smell, and feel of the fluid to identify the type of leak. Gravity pulls fluid down. Look to highest wet spot, unless spraying pressure leak or leak onto rotating part.

Diagnosis (7 of 7) Oil temperature and pressure switches.
Check when issue with gauge or warning light. Follow manufacturer’s troubleshooting procedures. Remember some oil will run from sensor’s hole.

Summary (1 of 9) Lubrication oil is distilled from crude oil and has additives to prevent acid formation, reduce oxidation, and maintain correct viscosity. Functions of oil include reducing friction, cushioning, cleaning, cooling, and sealing. Viscosity refers to how easily a liquid flows.

Summary (2 of 9) Oil additives include: extreme pressure additives, oxidation inhibitors, corrosion inhibitors, antifoaming agents, detergents, dispersants, pour point depressants, and viscosity index improvers. Engine oil also works to suppress engine noise, and protect against corrosion. The three types of oil are: conventional, synthetic, and synthetic blend.

Summary (3 of 9) Conventional oil is refined from crude oil and requires additives to function effectively. Synthetic oil is developed in a lab, is longer lasting, operates at higher temperatures, protects better against engine wear, and is more costly to manufacture. Synthetic blends combine conventional and synthetic oils.

Summary (4 of 9) The American Petroleum Institute classifies oil into groups 1−5. Components of a lubrication system include: oil pan, oil sump, pick-up tube, oil pump, oil pressure relief valve, oil filter, spurt holes, and gallery. Oil sump systems can be wet sump or dry sump.

Summary (5 of 9) Types of oil pumps are: rotor type, crescent pump, and geared oil pump. The two most basic oil filtering systems are full-flow filters (most common) bypass filters. Vehicles are equipped with oil indicators, oil monitoring systems, and some with an oil cooler.

Summary (6 of 9) Types of lubrication systems are: splash, pressure (or force feed), two-stroke engine premix, or two-stroke engine oil injection. Common lubrication system issues are: infrequent oil changes, oil leaks, and valve train noise due to low oil pressure.

Summary (7 of 9) Tools used to diagnose the lubrication system include: oil pressure gauge, mechanic’s stethoscope, digital volt-ohmmeter, and fluorescent dye. Diagnosis of the lubrication system may include: oil analysis; checking engine oil; oil pressure testing; inspecting oil sensors; and inspecting the engine assembly for fuel, oil, coolant, and other leaks.

Summary (8 of 9) Always check a vehicle’s service manual when changing oil to determine the correct quantity. If the vehicle’s oil pressure gauge reads low, verify this with a test gauge.

Summary (9 of 9) Lubrication repair tools include: oil filter wrench, wrenches and socket set, mirror, good quality light, digital volt-ohmmeter, and special socket for removing oil pressure switches or sensors. Maintenance and repair procedures include: draining the engine oil; replacing the oil filter; refilling engine oil; and inspecting, testing, and replacing oil pressure and temperature switches.

Credits Unless otherwise indicated, all photographs and illustrations are under copyright of Jones & Bartlett Learning.

CHAPTER 45 Engine Lubrication.

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CHAPTER 45 Engine Lubrication.

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