I have many years experience in engine oils and would like to share my knowledge and experience with all the lowyat.net forumer.
People often forget to read the description of the oil like API and ACEA specification in the labels to determine their suitability.
There are many commercial interest in the promotion of engine oils because oil companies with deep pocket are involved.
Sponsorship of F1 races is million or billion dollar expenses yearly so all the oil companies want to say their oils are good and so forth.
Of course as for all advertisement, there are a lot of myth(untrue claims) than the truth...
F1 formula racing as those that are advertised as champion oils are superior than others, synthetic oils are much better
especially multigrade 0W40, 0W60 are all over the advertising media.
However, Lubricants nowadays are very matured product with many standards. like American Petroleum Institute or API standard.
In the API classification and endorsement, (S for petrol engine, C for Diesel enginer) they have standard like SA, SB, SC,SD to
current SM and Diesel Engine Oil CA, CB, CD to currently CI.
The classifications are for the OEM engine maker who propose the specification for their new engine that needs a certain
properties and the additive maker like lubrizol and ethyl who formulate new additives to meet their new standards.
GF-4 and other european engine oils standards are also present for turbo charged and others special engines or for statutory
requirement like carbon and NOx emmission requirement.
Multigrade Viscosity and Viscosity index are usually in the specification but not in the spec so you need to search for it in google.
Lubrication is about the engine oil films between 2 surfaces. So the thickness(kelikatan) becomes the key point. In trobology
term, piston lubrication is hydrodynamic lubrication where the oil firm separate 2 moving surfaces completely in high speed
movement. But Oils will thin out when heated, just like if you overheat your oil pan when you goreng your pisang, sometimes
your oil pan also catch fire. Oil thin out at high temperature and oil evaporate and at the fire point can cause fire.
To define a suitable engine oil, 2 important characteristic called viscosity index and multigrade properties are describe like
VI-160, 0W40, API-SM. Which essentially means that this oil has a higher VI( normal mineral oil is 95) with a flow properties
of SAE "0" at 0 degree C and SAE 40. In cooler country with winter low temperature, the flowability is a problem so they need
a engine oil that can flow at low temperature but still can maintain sufficient oil film thickness at high temperature.
Higher VI means the viscosity would tend to change less at different temperature.
My Opinion 1
In tropical region like Malaysia, there is no significant differences to use multigrade engine oils in Malaysia even at cool start up
because the engine temperature would not be lower than 20C so the different in viscosity is minimum eventhough your car
manual stated you should use 15W40 oil.
But Castrol Magnetic claims that most piston wear occur during the start up and their oil contain ester which has polarity to stick to
the metal surfaces so at cool start without engine oil it protests.. Some exotic engine oil seller even claims that they drain out all
the engine oil, to go Genting highland and come back, but the engine still would not seize up.
My Opinion 2
I am doubtful about the Castrol Magnetic claims because oil will always stick to the surfaces(always polar),
oil pump is link to the engine so as fast as the engine turn the oil flow to the piston. Of course some car that give 3 to 5 years
guarantee on piston actually has their engine coated with solid lubricants like MoS2. Most exotic additives like FIR something are
too expensive that you may not want to buy just to expect one day your engine oil is gone and you are running with dry engine
with the additive.
Once you car goes into workshop, some enterprising mechanic will recommend you many things, among others are the so called
black oil concentrate. So what are black oil concentrate..The main component of black oil concentrate are X. Viscosity index improver
Y. EP additives Z. Friction modifier. Let goes back to the basic components of a engine oil. A gasoline or Diesel engine oils are
blend(mixture) of 2 or more types of base oils with a viscosity index improver and cocktails of lubrizol or ethyl additives.
Base oils are described as K.Mineral Oils H. Hydrocracked group 2 base oils I. Group 3 PAO and Ester.
My Opinion 3
Normal mineral oils for API-CF or API-SL engines (<RM70/4ltr) are the mainstream products today because we Malaysian uses
more old car. When your car manual recommend you to use this grade oil oil, it is sufficient to do it work. You do not need a
black oil concentrate any more. If you car is more than 10 years oil and has develop some engine problems black oil concentrate
probably cannot help because it is usually a mechanical problem. (P1. diesel engine black smoke are caused by block diesel fuel
nozzle P2. Gasoline engine need top up regularly is usually due to leakages or piston rings) It is silly to buy a RM50 low grade ABC oil
and add black oil concentrate for RM30 per bottle x 2 inside because the total cost would be like a semi-synthetic engione oil..(sorry
to all the black oil concentrate seller...)
SAE 0W20 and 0W60 viscosity grade are for professional use. Because the lighter the oil, the more fuel saving it is. So if you got
a new car and you don't mind a louder engine sound, you can use SAE30 or 0W30 because the thinner oil cause lesser friction than
a thicker SAE40 engine oil saving about 5% more fuel. Kancil type of ligh vehicle uses SAE30 as spec-in. 0W60 are for racing use
because if your engine are under great stress like in racing and when the protection of your piston is your primary objective than the fuel
efficiency then a thicker oil is good for you.
But if a car using a synthetic oil can it extend engine oil drain interval ?. This is a very common question but common sense will tell
you the answer. Let look at a engine oil composition again, it is 85% base oils** 8% viscosity index improver and 7% cocktails of
other additive. Commercial products plays with the 2 seemingly confusing term like "synthetic blends" and "fully synthetic".
The differences between the 2 are "synthetic blend" is actually the semi-synthetic ; usually 15% of PAO or ester or Hydrocracked
base oil with the rest of the component as mineral oils while fully synthetics are esters and PAO or a mixtures between the 2.
A mineral oil type of engine oil are usually blended for it recommended drain interval for 5000KM intervals only for petrol
and diesel passenger car. It is blended using mineral oils which is refined from crude oils and contain heat or chemical unstable
hydrocarbon structure when compared to synthetic man made PAO and ester. These lower priced products also may not have
stable viscosity improver that maintain its viscosity characteristics. If you are driving more continuously like outstation using a
synthetic PAO and esters will be more able to withstand higher engine temperature without accelerated oxidation, breakdown or evaporation.
Every 10C increase in temperature the mineral oils life will become half of its original life.
My Opinion 4
Most of us use 2~3 hours driving a day so normal mineral oils will be sufficient.
When considering oil drain intervals using different type of engine oil products, convenience, fuel efficiency and oil conditions
are the primary consideration. Any oil change between 5,000km to 10,000 km is reasonable, any addition of additive to extend
it further would be unnecessary and pose many risks. Contamination is the greatest risk like fuel dilution and soot or ash formation inside the
engine oil. If you check your engine oil level regularly and your fuel efficiency regularly, it would be a good time to change
the engine oil when your fuel efficiency drop or the engine oil level drop because of evaporation and burn off. Of course you have
to check your tyre pressure to ensure other factor does not effect the 2 factors. (a low pressure tyre will cause 15% drop in fuel
efficiency) In 3 months if you buy RM2000 in petrol or diesel but your engine oil will cost RM100 or below, you will understand that
lubricant is typically 5% of your cost. Buying of semi-synthetic or synthetic blends is confusing because you never know how many
% of sytnthetic PAO/ester is inside although the latest API-SM GF-4 will make obsolete the solvent refined mineral oil because engine
oil blended from it will not pass the test required.
Similarly any additives that cost more than RM100 but claims to only save 5% fuel is also not justificiable. Some technical research
data shows that soluble molybdenum disulphide can actually do that but their cost is usually more expensive.
In conclusion, engine oil use are in accordance to the year of production of your vehicle. My 9 year old diesel car is good using normal
API CF-4 15W40 while the latest 2010 model of most petrol engine car would use API-SM GF-4 for superior oxidation stability and fuel saving.
Any additive addition may not be required in a properly manufactured engine oil product as in accordance to the API and European standards
as their effect cannot be fully understandable or redundant and add to cost. For example the API-SM GF-4 has many tests that set maximum
% evaopration in engine testing rigs and lower friction test compared to previous API-SL. More oil changes to avoid contamination than
expensive engine oil in many confusing term is advisable. Proton and Japanese car manufacturers do not recommend extended oil drain (> 5,000km )
although 10,000km oil change is normal in American and European car for the simple reason of more service more income.
* RX-7 /8 is a rotary engine and the engine oils used are different from piston engine and they are not interchangeable.
** Mineral Base oils is about RM2.4/litre while POA is about RM30/litre
Any comment welcome.