Most people just flick the ignition key and drive their car without thinking of what is going on under the hood.  This is fine, as most cars today require little maintenance as long as the car is serviced at regular intervals there is nothing to worry about.

Has anyone ever considered that a car is almost like a living organism? and is so similar to a person that its quite remarkable when we compare it, for example we could say that  the bodywork equals the human body, the horn equals the voice, the radio equals the ears, engine equals the heart, carburettor equals the nose and lungs, air filter equals the mucus membranes, oil filter equals the kidneys, gasoline filter equals the liver, axle and wheels equals the legs and feet, headlights equals eyes, gasoline tank equals the stomach, the gasoline pipes equals the intestines, the wiring loom equals the nervous system, the oil pipes equals the veins and the motor oil equals the life blood.

Each component plays an important part and indeed the motor oil is the life blood, be it of your car, motorcycle or truck, motor oil is the life blood of any engine.  It is therefore quite important that you have the right "blood" flowing through your engines veins.

Motor oil is a substance like liquid grease that lubricates all the metal to metal working surfaces in the engine.  It does this by vastly reducing friction and also transfers some of the heat away.

If there was no motor oil in the engine then the engines metal to metal parts would get exceedingly hot, start to seize up and  even melt.  Consequently the engine would seize up solid in effect destroying it, henceforth motor oil is a very important engine criteria.

If the little red "oil light" that looks like an oil can  symbol illuminates whilst you are driving your car, then pull over and stop immediately.  This light indicates that you have low engine oil and are about to start incurring serious damage to the engine.

You need to top up the engine oil by pouring at least ½ liter of motor oil into it.  This is very easy to do, lift the hood, under the hood, unscrew the filler cap on the engine, usually marked with an oil can symbol as seen below...and pour in the oil. 

Check the dipstick, pull it out, wipe it dry then re insert it. There are lines or notches on the end of the dipstick, the oil should wet the top mark or top notch.

Engine rebuilds are megga expensive and you can save damage by just topping up your engine oil.  Also make frequent checks under the hood.


Selecting the right oil for you engine is sometimes one of the last things that anybody considers when that all important "blood transfusion" or rather...the oil change comes around.

Oil is not just oil, there are many different types available, each one with different variables to tailor specifically for your engine.  Almost like different blood groups.  It best to have the right blood group for your engine.

The car doctor at the surgery, or rather the mechanic at the garage may make some recommendations as to which is the best oil for you car, its best to go along with their advice.

Different engines such as diesel, gasoline, high performance, low performance all need the most suitable motor oil for the stresses that the engine will endure.  Just like having high or low blood pressure, where an aspirin waters the blood down so it flows better, the viscosity of engine oil is the same principle.

There are many different oil companies and they all make a wide and various array of different oils, they also provide important information about their motor oils.

This information is known as "typical inspection data" or t.i.a.  This data basically states the actual physical properties of the oil and also refers to any chemical additives.  This data is generally available to the discerning motorist via the oil companies vendors, i.e...the place where you bought the oil from.

There are basically six properties of motor oil that are generally publicised for considering which is the best oil for your vehicle.  These properties are the viscosity index (VI),  viscosity, pour point, flash point, sulphated ash % and zinc %.

The viscosity is the thickness of the oil or how easily it flows. An oils viscosity is important is it physically stipulates how much stress the motor oil can handle during extreme ranges of temperature in reference to how it flows when under these stresses.

Motor oil that is thin has lower viscosity and a thicker motor oil has higher viscosity, the viscosity is important when regarding the engines output.  Low viscosity oil can lose performance at high temperatures and a high viscosity oil can lose performance at low temperatures.

To explain in further detail, high viscosity oil may not flow to all the necessary parts of the engine at lower temperatures.  Also high engine revolutions (r.p.m) can tear the film of protection with high viscosity oils and low viscosity oils can have the film of protection torn at high temperatures.

Motor oil is put under very high stress, it has a limited life and hence needs to be changed every so often because of this.


The S.A.E ( Society of Automotive Engineers) allocate all the different arbitrary numbers for the different "weights" of motor oils.  These numbers are in direct relation to the viscosity of the motor oil and help the auto industry and the motorist know what the "grade" of oil is.

These grades are assigned to the oil when they are measured at specific temperatures.  The grade of oil then falls into certain categories of viscosity designated by the numbers 5W, 15W, 10W, 20W, 30W, 40W, 50W and even 60W

Each number is preceded with a letter "W" this letter basically indicates "Winter Weight" and refers to the viscosity of the oil and its potential to work in very cold weather.  A 5W oil for example will still keep its same viscosity right down to -25 degrees centigrade.

These motor oils will therefore all work reliably and dependently  at their stated low temperatures:

 5W @ -25C, 10W @ -20C, 15W @-15C and 20W @ -10C

If you were to live at the North Pole then a 5W oil would be best suited and if you lived in the U.K then a 20W would be okay as the temperature in the U.K very rarely goes below -10 degrees centigrade.

Modern motor oils can now be of the multi-viscosity variety and will not thin out as much as the oil gets hotter.  This is due to additives in the oil such as polymers, these polymers being a careful concoction of chemicals that govern the oil to work in a particular fashion.

For example oil that has reached 100 degrees centigrade will only thin out to a specific amount and no more.  So a 20W-50 oil is a 20W oil that will not lose viscosity more than a 50W oil would when at 100 deg C.

Multi-Viscosity oils are retailed to the public as "Multi-Grade" oils and they should be selected properly.  If for example you have a high performance sports car then a multi grade oil would not be a good choice.  The engine is going to work harder and get hotter quicker so the viscosity will need to alter quickly to suit.


A basic rule of thumb is  that in the winter  the lowest temperatures need consideration whereas in the summer the highest temperatures need to be considered.  If you have a high performance sports car in the blazing Arizona sunshine, it will be a different grade of oil to that of driving the same car in the Arctic Tundra.

Microscopically the different polymer additives can tear and burn away ( oil being a combustible) and can then leave a film of sticky deposits of oil emulsion that can cause the piston rings to stick, also inducing fouling and abrasive properties...this is when the oil actually works in reverse of what its supposed to do...lubricate and protect the metal to metal surfaces.

Also oil that has not been changed in a while gets full of carbon deposits and feels gritty to the touch, this oil also starts to work in reverse of its prime alleviate friction and abrasion.

10W-40 and 5W-30 motor oils have a lot of polymer additives in and can cause problems in diesel engines, diesel engines of course being very high compression engines.  The least amount of polymers are the best sort of oil for most engines regardless whether they are gasoline or diesel.

High polymers oils are more liable to viscosity breakdown at higher temperatures and greater stresses.  To take a step back and look at it logically it is only the oil that lubricates and reduces friction, the additives actually reduce the oils ability to work 100%.

The viscosity index (VI) indicates how fast the actual viscosity of the oil changes as high temperatures are reached.  If the VI number is high then this indicates that the viscosity does not change very much, it is a low change.

A lower VI number indicates that the oils viscosity will alter as soon as the engine starts to heat up...this is suitable for dragsters and race cars that go from 0 to 60mph in seconds.

So it can be determined that for a family car a higher VI number is better and it offers thicker protection for longer and doesn't thin out into high performance oil for non high performance running.

The flash point of the motor oil is the temperature at which the oils starts to vaporize into an ignitable vapor by naked flame.  Measured in degrees Fahrenheit,   a low flash point oil of say 350F is more liable to vaporize at high temperatures, the engine then becomes an "oil burner" as the oil burns away in the hot engine.

Therefore a high flash point oil of 400 F and higher is the best to have and will save money on constant motor oil top ups.

Another criteria of motor oil is the pour point, or the point at which chilled motor oil @ five degrees Fahrenheit remains static on a slight slope for five seconds before it moves.

This way of grading the viscosity is important to indicate the best motor oil for winter use, as we have to remember that cold motor oil will be reluctant to circulate as well as warmer oil that has thinned out slightly.  The pour point is not publicised with most oil companies as is all basically tied up in the oils viscosity grade.

The percentage of sulphated ash indicates how many solids remain when the oil is reacted with sulphuric acid and burned off.  This sulphated ash percentage is primarily used by oil companies to dictate oil additives metallic wear inhibitors and performance relation in association with detergents and polymers in the oil. 

The test specifically examines the anti-wear properties of zinc dithiophosate detergent that help to stop the oil from clogging.

The zinc percentage relates to the amount of zinc that is used as an extreme stress and high pressure additive to prevent wear.  The zinc apparently works when the oil is compressed between metal to metal surfaces such as the pistons movement. 

The oil itself should prevent wear, in doing its prime directive but if the oil fails to do this then the zinc microscopically reacts with the metal surfaces and hinders additional wear.

Motor oil with an 11% zinc amount in it will offer the extra protection needed and this amount is generally added to most if not all motor oils.  Motor oil for high revving engines on performance sports cars and air cooled motorcycles should really have a higher zinc content as it will give extended protection of all metal to metal surfaces.

Just to emphasise that zinc will not give higher upgraded protection it just protects longer, consider a bike engine working at 14,000 r.p.m whereas most car engines run at 2,500 r.p.m....big difference isn't it!

Just to note here, for those that have done their own oil change and noticed a grey residue in the oil...this is the zinc compound that has been literally  thrashed out of the oil.

It all sounds like rocket science and in many ways today's motor oils are developed in the same environmental class.  Motor oil manufacture it is a highly complicated and technical procedure whereas biologists, scientists and physicists are employed to help create the oil.

Fully Synthetic Characteristics
Increased fuel economy, increased engine performance with more power. Increased engine protection and reduction of deposit, sludge build up. Increased cold starting protection and increased oil flow properties in freezing weather conditions.  Four time the protection of normal oil. Generally a superior motor oil for all occasions.  Much more expensive than semi-synthetic and mineral oils.
Semi Synthetic Characteristics
Good protection with some fuel savings.  Decent protection within the first critical moments of starting up the engine.  Three times more protection and increased oil change intervals.
Mineral Oil Characteristics
Standard engine protection for practically all engines but regular oil changes are needed more often. Slower to circulate in freezing conditions hence more engine wear and also slower to adjust to the engines temperature hence engine not as efficient and some horsepower loss.


Synthetic motor oils are now very popular and are outselling the normal variety of petroleum based oils.  Synthetic motor oils offer superior operational characteristics in all temperature ranges, from exceedingly cold to exceedingly hot.

Synthetic motor oils are not so liable to leave any deposits, they have supreme viscosity properties of stability and can flow just as well at low temperature as they can in high temperatures.  Synthetic oils consequently cost more but in the long run are worth it for their superior qualities.  As one motor oil company stated about their synthetic oil  " Its Liquid Engineering"

Synthetic motor oil does not need to be changed as regularly as normal oil and can easily manage 30,000 miles in most family cars.  Of course there are various attributes to the longevity of the motor oil in a vehicle, the climate, the average engine speed and the stop and go factor.

If the vehicle does slow trips over short distances that do not even let the engine get up to normal temperature then the oil is also adversely effected over time and will actually need to be changed earlier...some mechanics suggest every 5,000 miles if the vehicle is driven like this.

Fully synthetic motor oil can actually last up to three or four times longer than normal mineral oil and can be cost efficient in needing less maintenance and top ups.

Castrol Edge appears to be one of the best oils at the moment and Castrol have this to say about their new motor oil. "Castrol EDGE with SYNTEC Power Technology has a unique and proprietary formula that reduces volatility and provides superior protection for critical engine parts helping your vehicle operate efficiently at maximum power.

Castrol EDGE with SYNTEC neutralizes acids in your engine that can cause rust and corrosion on vital engine parts such as cylinders, bearings and hydraulic valve lifters as well as providing stability and endurance under extreme conditions (heat, load, speed) that can cause conventional oils to break down "

Some of the best performance motor oils are presented below.

Mobil 1 Supersyn 0W-40

For Turbo Diesel engines. Is the ultimate performance, super synthetic engine oil designed to provide unsurpassed protection for the engines of all diesel powered passenger cars, light trucks and vans.

Mobil 1 Supersyn Motorsport 15W-50

This oil is for the racing enthusiast or owners of high performance cars, who want to access the technology used by the world's leading motorsport teams. 100% super synthetic lubricant developed for the highest performing engines.


5W-30 ESP Formula

The very latest Mobil 1 specification expertly engineered to promote the life of your vehicles emission reduction system, including catalytic converters and diesel particulate filters.

Approved to VW, Audi, BMW and Mercedes Benz latest long life specification. 


Castrol GTX High Mileage 10W-30

Castrol GTX High Mileage 10W-30 Motor Oil is formulated with unique additives to protect engines with more than 75,000 miles from wear and harmful deposits.


            Castrol Power RS 4T 5W-40 Motorcycle Oil

Castrol Power RS R4 4T with Trizone Technology is a fully synthetic 4 stroke engine oil for high performance bikes. Its Race Proven Technology based on Castrol's extensive history and testing experience ensures optimum engine performance to help provide increased acceleration under the most arduous riding conditions.


                           Castrol EDGE Sport 10W-60

 Castrol EDGE Sport 10W-60 is a hard wearing, fully synthetic engine oil for use in a wide range of sports performance engines and older modified vehicles. This product has been tested in race engines to deliver protection in hot and hard running scenarios. Castrol EDGE Sport 10W-60 is suitable for tuned or high performance vehicles. 


Pennzoil 5W-30 Motor Oil

Pennzoil 5W-30 Motor Oil contains active cleansing agents that prevent deposits and sludge build up to keep your vehicle's engine clean and responsive.


               Pennzoil High Mileage Vehicle 10W-40

Pennzoil High Mileage Vehicle 10W-40 Conventional Motor Oil uses active cleansing agents to continuously help prevent dirt and other contaminants from turning into performance robbing deposits in vehicles that have accumulated more than 75,000 miles.


Valvoline Maxlife 5W-30 High

MaxLife Full Synthetic Higher Mileage Motor Oil gives your engine the greatest protection available against oil burn off and friction with synthetic engine oil. MaxLife Full Synthetic Higher Mileage Motor Oil gives your engine the greatest protection available against oil burn off and friction with synthetic engine oil. 

It all sounds very confusing, knowing which is the best motor oil for your pride and joy. In this modern day and age though, your worries can be put to rest as most garages will only use the best motor oil for your car, unless you specify differently.

If you are a car enthusiast and like to rebuild and modify engines then you are more at liberty to buy your own specific motor oil.  In most cases car enthusiasts won't spare the decks for eight pence worth of tar and will buy the best fully synthetic motor oil to give the best performance and protection to the heart of their machine.

I myself always use either Mobil 1 Supersyn  or Castrol Magnatec, all of which are fully synthetic.  I no longer use any additives such as Molyslip, as they are not needed with today's high tech motor oils.




Page created 3rd July 2012