OIL SPECIFICATIONS
What is oil viscosity a.k.a. oil weight? Viscosity Viscosity is a fluid’s resistance to flow. In case of lubricants the viscosity is very important because it affects the oil’s oil’s ability to reduce friction friction and transfer heat. The viscosity is measured in mPa*s (millipascal-seconds) but in everyday life we don’t d on’t use the actual measured viscosity we use viscosity !rades instead. These !rades also "nown as #wei!hts$ were set by the %&' (%ociety of &utomotive 'n!ineers) and in order for a fluid to fall in a !iven cate!ory it has to meet certain limits. These limits are listed in the %&' table+
The numbers that have a , after them are the so-called winter viscosities while the numbers that don’t have a , are the so-called summer- or operatin! temperature viscosities. %everal decades a!o motor oils either fell in one of the winter viscosities or in one of the summer viscosities. These products were mono!rade oils and car owners had to chan!e oil at least twice a year+ once for the winter and once for the summer. Than"s to the synthetic base oils and the viscosity modifier additives nowadays most motor oils are so-called multi!rade oils that don’t chan!e their viscosity with temperature that much so they meet the limits of a winter and that of a summer viscosity !rade at the same time. These oils can be used re!ardless of season. ono!rade oils are still used for special purposes but usually not as en!ine lubricants.
What is the best motor oil viscosity? There is no sin!le best motor oil viscosity. &s a rule of thumb always follow the car manufacturer’s recommendations. lder cars are usually o" with a /,- oil while newer cars usually li"e a lower viscosity oil li"e 0,- ,- ,- or sometimes even ,-1. ,-1. It’s important to "eep in mind that viscosity is not the only important property of the oil+ if there is any special specification (e.!. &PI %2 or 3 4e5os 1) re6uired by the car manufacturer then the oil should meet that specification and should also be the correct viscosity in order to be used for that particular vehicle.
What is the viscosity index? Viscosity (actual viscosity not the viscosity !rade) chan !es with temperature. The hotter it is the lower is the viscosity the colder it is the hi!her is the viscosity. 7owever the de!ree of this temperature-related chan!e of viscosity is not the same in case of every oil. %ome oils chan!e their viscosity more when temperature chan!es some chan!e less. Those that chan!e less have a hi!her viscosity inde5 those that chan!e more have a lower one. (8emember the discussion about the mono!rade and multi!rade oils before9 ono!rade oils’ viscosities chan!e more as temperature chan!es multi!rade oils’ chan!e less so multi!rade oils have hi!her viscosity indices.) ,e li"e oils with hi!her viscosity indices more because it means that the oil is more stable viscosity-wise. :or lubrication purposes there is an optimal viscosity and the less the oil deviates from this optimum the better. %ynthetic oils have hi!her viscosity indices ma"in! them superior to the mineral oils in this re!ard as well.
Why change the motor oil from time to time? The motor oil costs only a small fraction of the total amount that you spend on your car but choosin! the ri!ht oil can save you lar!e sums. ;ow 6uality or overused motor oil is not capable of fulfillin! its duties and can cause a series of problems. ,e are !oin! to introduce the most important motor oil related problems their usual causes and con se6uences.
Deposit formation Possible reasons+ additive depletion or contaminated motor oil. Possible conse6uences+ pre-i!nition reduced power hi!her emissions.
Wear Possible reasons+ abrasive physical particles in the motor oil additive depletion motor oil contamination or too low motor oil level. Possible conse6uences+ en!ine component failure or en!ine brea"down.
otor Oil !iscosity Increase Possible reasons+ additive depletion motor oil o5idation and motor oil contamination. Possible conse6uences+ motor oil circulation problems wear of critical en!ine components mechanical problems.
otor Oil Thermal "rea#$o%n Possible reasons+ additive depletion motor oil o5idation abnormally hi!h en! ine temperature. Possible conse6uences+ motor oil thic"enin! oil starvation cold start problems en!ine failure.
otor Oil Circ&lation Pro'lems Possible reasons+ motor oil pump malfunction clo!!ed oil passa!es too low oil level. Possible conse6uences+ low motor oil pressure wear of critical en!ine components mechanical problems.
(o% to A)oi$ These Pro'lems?
These problems can be avoided by usin! 6uality motor oils and by respectin! the factory recommended oil drain intervals. & 6uality motor oil contains all the additives that are re6uired to prevent these problems so there is no need for aftermar"et additives for en!ine flush or for chan!in! the oil more fre6uently than recommended by the '. &n e5ception from the last rule is when the operatin! conditions are tou!her than normal since those conditions re6uire the shortenin! of the oil drain interval.
What Are The *easons of Oil Cons&mption? ne of the dreaded thin!s car owner face is oil consumption. :or some people the only time when they have to do anythin! motor oil related is the time when they find out that its level is too low so it needs to be topped up. That’s assumin! that the re!ular oil chan!e is done by the repair shop and not the owner. It’s easy to thin" that the oil consumption is the oil’s fault especially if you didn’t notice it until the last oil chan!e. The truth however is not so simple. il consumption has many reasons . ;et’s !o throu!h the most common ones 6uic"ly+ •
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Engine design. Some engines consume oil by design. From day 1. The consumption can be as high as 1 liter per 1000 kms (cca. 1.7 quarts per mile). This depends on the make and model o the engine so i oil consumption matters to you a lot then you are better o! asking questions on the orums about it. "ri#ing style. $%& a!ects oil consumption. The higher your usual $%& is the more oil 'ill be consumed. Thats because you put etra pressure on the seals and gaskets and some o the oil *nds its 'ay around and gets burned a'ay in the combustion chamber. Seal and gasket condition. The more 'orn they are the more oil 'ill be consumed. +hat happens is the same thing that , mentioned in the pre#ious section- the oil *nds its 'ay around the seals and it gets burned a'ay in the combustion chamber or it simply leaks out. igher/than/normal engine temperature. The hotter your engine runs the thinner your oil 'ill be. nce again it 'ill be simpler or a thin oil to reach the combustion chamber and get mied and burned 'ith the uel. Too/lo' #iscosity motor oil. , you use an oil 'ith a #iscosity belo' the recommended by the engine manuacturer than you 'ill eperience oil consumption or the same reason as presented in the pre#ious section. y #iscosity , do not mean S2E #iscosity only. The TS #iscosity also counts. For eample you could eperience higher oil consumption 'ith lo'er TS #iscosity 23E2 2141 oil than 'ith a higher TS #iscosity 23E2 2545 oil. 6o' quality motor oil 'ith high #olatility. , mention this as the last one because this is the least common reason. , the oils #olatility is #ery high than it could be noticeable in the oil consumption rate.
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There are also numerous other reasons including but not limited to high oil le#el the damage or clogging o di!erent engine parts and the uel contamination o the oil.
" so these were the reasons let’s see what you can and can’t do about it + •
This is the most important- do not automatically try a higher #iscosity oil to combat oil consumption. First consider the ollo'ingigher #iscosity means 'orse cold temperature perormance slo'er o oil circulation higher oil pressure less heat transer and 8 sometimes i the oil passages are thin 8 'orse lubrication e#en on operating temperature. o
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This does not mean that the lo'er the motor oils #iscosity is the better the oil. ,t 9ust means that you should al'ays stay 'ithin the range speci*ed by the manuacturer and ne#er use a thicker oil than allo'ed only to decrease oil consumption. Think about it- you could put grease in the engine instead o oil and there 'ould be no oil consumption but your engine 'ould ail in seconds or minutes. So no oil consumption does not mean better engine lubrication nor longer engine lie.
:ou could ha#e your engine checked or 'orn seals and gaskets especially i its a high mileage engine. , you had no oil consumption problems 'hen your engine 'as ne' and no' you ha#e since its old then this is the most probable cure or your engine. :ou could use an engine oil stop leak additi#e to reduce oil consumption but this should only be a temporary solution because it doesnt treat the underlying cause o the consumption it 9ust hides it. :ou could change the oil to a ully synthetic type i you are not using such oil already. Synthetic oils ha#e a lo'er #olatility so this can also ha#e an impact on the oil consumption. 3hange your dri#ing/style to stay bet'een ;/;.
L&'rication glossary
A$$iti)e 2 compound mied to the base oil in order to modiy its properties or perormance. "ase Oil =sually re*ned crude oil raction or selected synthetic base stock. 2dditi#es are mied to them during lubricant manuacturing. Total "ase N&m'er +T"N, The amount o acid required to neutrali>e the lubricants basicity epressed in ? equi#alent. Detergent A$$iti)e 2n additi#e mied to uel and lubricants in order to keep the engine clean. The most used detergent additi#es in motor oils are metallic soaps that ha#e enough base reser#es to neutrali>e the acids ormed during engine operation. Po&r Point ,ndicates the @uidity o the oil or uel on lo' temperature. ,ts the lo'est temperature on 'hich the @uid still @o's. Dispersant A$$iti)e 2n additi#e 'hich keeps the solid contaminants in colloid suspension thus pre#ents the oil sludge and #arnish buildup on the engine parts. This additi#e is usually non metallic (ashless) and its used together 'ith detergent additi#es. DPF +Diesel Partic&late Filter, The "%F is a physical *lter that reduces the solid particle content o the ehaust gases. *ing Stic#ing $ing sticking occurs 'hen the piston ring sticks into the groo#e due to ecess contamination. E-* +E.ha&st -as *ecirc&lation, 2 system designed to reduce the A emission. ,t recirculates the ehaust gas back into the intake maniold thus diluting the uel4air miture and reducing the temperature and A ormation. Pre/ignition %re/ignition is the combustion o the uel4air miture that occurs in internal combustions engines beore the spark plug *res. Typical reasons are the hot uel or the lubricant buildup in the combustion chamber. ,t reduces engine po'er and it can damage the engine. EP A$$iti)e 6ubricant additi#e that pre#ents the sei>ing o the sliding suraces under etreme pressure conditions.
*e0ning 2 series o processes through 'hich the crude oil is con#erted into a petroleum product. Such processes include- thermal cracking catalytic cracking polymeri>ation alkylation reorming hydrocracking hydroorming hydrogenation hydrogen treating sol#ent etraction de'aing de/oiling acid treating clay *ltration and deasphalting. Anti foam a$$iti)e 2n additi#e to reduce the oaming o petroleum products. 3an be silicone to destroy the surace bubbles or polymer to reduce the count o small internal bubbles. Ash &etallic residue ormed due to the high temperature in the combustion chamber or on other engine parts.
(y$ro0nishing ydrogen treatment o crude oil in order to saturate the molecules and increase stability.
(T(S +(igh Temperat&re (igh Shear, !iscosity 2 measure o a @uids resistance to @o' under conditions resembling highly/ loaded 9ournal bearings in *red internal combustion engines typically 1 million per second B 1<0 C3. Catalytic Con)erters idi>ing catalytic con#erters remo#e hydrocarbons rom the ehaust gas 'hile reducing catalytic con#erters reduce the A emissions. oth types contain noble metal (platinum palladium or rhodium) 'hich can be poisoned by lead or phosphorous present in uel or lubricants. L&'rication The reduction o riction and 'ear using a riction/reducing layer. This layer can be liquid solid or plastic. 1inematic !iscosity The @uids resistance to @o' 'hen a!ected by gra#ity. =sually measured on D0 C3 or 100 C3. !arnish Thin insoluble non/'ipeable layer on the internal parts o the engine. ,t can cause the sticking and breakdo'n o internal mo#ing engine parts. Anti/Wear A$$iti)e 2n additi#e that creates a thin layer 'ith good adhesi#e properties in order to pre#ent metal/to/metal contact at high/load spots. Corrosion Inhi'itor 2n additi#e that protects the lubricated metal parts rom the chemical attacks caused by 'ater or other contaminants.
Flash Point &inimum temperature at 'hich a @uid 'ill support instantaneous combustion but beore it 'ill burn continuously. The @ash point is an important indicator 'hen determining the *re and eplosion ha>ard o a petroleum product. Oil sl&$ge Thick dark residue 'ith mayonnaise/like consistency 'hich builds up on the non/mo#ing inner parts o the engine. ,nsoluble contaminants in the oil accelerates its buildup. O.i$ation ccurs 'hen the petroleum product reacts 'ith oygen. The process is accelerated by heat light metallic catalysts 'ater acids or the presence o solid contaminants. O.i$ation sta'ility 2 petroleum products resistance against oidation. 2!ects product lie both in storage and in use. Total Aci$ N&m'er The required amount o ? to partially or ully neutrali>e the petroleum products acidity. Friction The resistance that occurs 'hen one ob9ect is mo#ed on another ob9ect. The riction depends on the smoothness o the sliding suraces and on the orce used to press them on one another. Synthetic 6ubricant 6ubricant made o speci*cally composed chemically reacting substances that has pre/determined properties and characteristics. %umpability 2 lo'/temperature property o the oil 'hich determines to 'hat etent is the oil capable to @o' to the pump on lo' temperatures. &ultigrade il 2 motor or gear oil that meets the requirements o more than one S2E #iscosity grade and thus it can be used in a 'ider temperature range. Tribology Science branch dealing 'ith riction 'ear and lubrication. iscosity 2 @uids resistance to @o'. iscosity inde The relationship bet'een a @uids #iscosity and temperature. Fluids 'ith a higher #iscosity inde change their #iscosity to a lesser degree due to the change o temperature.
iscosity modi*er 6ubricant additi#e usually a polymer that pro#ides bene*cial rheological properties to lubricating oils such as reducing the tendency o an oils #iscosity to change 'ith temperature.
