Your piston rings do not do a perfect job of sealing. Some combustion by products will slip past the rings into the engine. This can be little particles of carbon. Remember, diamond is carbon that was combined under heat and pressure. These little carbon particles can be quite damaging to your engine. Another job of your oil is to hold these particles in suspension until the oil filter can grab them. Also, if your gasoline has sulphur in it (it does), this sulphur can react with water and oxygen to make sulphuric acid. This is some stuff that is seriously bad for your engine. Your oil has special ingredients in it called buffers to neutralize acids. Finally, your engine can get internal build ups of tars, waxes, and other gunk. Your oil has solvents to try to dissolve this stuff and get and keep your engine clean.

Motor oil types

Motor oil brands

There is plenty of motor oil companies out there to choose from. It can be a difficult task to pick which one is the best. Everyone has their own opinion about brands of motor oil. There are a couple of things to consider when choosing motor oil.

• History
• Credibility
• Market situation
• Car manufacturer’s preference

The history of every oil company should be investigated before you decide to use their oil in your vehicle. Vehicles are one of the most expensive investments of your life time, and the oil you choose is the life of your engine. Several oil companies have bad reputations for things they have done in the past regarding their oil. Some companies have used bad mixtures, inadequate lubrication properties, faulty chemicals, and other neglectful choices that lead to harm of your engine.

Credibility of the oil company you choose should be on the top of your list. Consider using the major oil companies that racing teams use. Racing teams should be your first indication of the quality of the oil you are considering to use in your vehicle. Of course there are the big name teams supporting garbage oil, but look into amateur racing teams and see what they say. These teams are on very tight budgets and will only use the best oil possible.

Also, talk to other car enthusiasts that have turbo forced induction vehicles. Owners of turbo cars that take special care in choosing oil will always know what the best oil to use is. Turbo forced induction vehicles put oil to the test by the heat created. If oil can withstand a highly tuned turbo vehicle, it’s a good bet it’s safe to use in the average car.

The market situation and current economic problems can cause oil companies to short change the consumer by adding chemicals that reduce the amount of oil per gallon purchased. This increase of additives reduces the life of the oil by creating more molecules that are susceptible to thermal breakdown and degradation. Larger companies aren’t always the best choice, because the bigger they are the harder they fall. When times are tough, all businesses tighten up and secure profits. Don’t let your motor oil become a victim of profiteering.

What is the best motor oil?

I drive a turbo forced induction vehicle and have been conducting research about oil for several years. It is my opinion that “Mobile 1″ full synthetic is the best motor oil for the money while “Royal Purple” synthetic is the best motor oil over all. Royal Purple synthetic is chosen by several racing and rally teams as their lubrication of choice. Mobile 1 is a highly regarded racing lubricant used in all forms of motor sports. The big guys choose Mobil 1, while the small racing teams and avid sports car enthusiasts prefer Royal Purple. If you can afford the Royal Purple, get it.

Either way, I strictly prefer synthetic oils over conventional and blend. Synthetic oils are made in a laboratory and therefore as close to perfect chemical composition as possible. Less amount of additives in synthetic oil also create a more stable lubricating product than that of counter parts containing several additives, detergents, etc. Synthetic oil also does not create as much energy strain on the environment because the oil you are using is not pumped out of the ground; it’s made in a lab.

Take Castrol for example. They led the field for years with GTX. This was surpassed a few years back by semi-synthetic and fully synthetic oils, including GTX2 and GTX3 Lightec. Now, that’s been surpassed by Formula SLX which can cost upwards of $75 for 5 litres. And most recently, Castrol GTX Magnatec which is muscling in on the hitherto separate world of friction reducers.

What does my oil actually do?

The point of engine oil is primarily to stop all the metal surfaces in your engine from grinding together and tearing themselves apart from friction whilst transferring heat away from the combustion cycle. Engine oil must also be able to hold all the nasty by-products of combustion, such as silica (silicon oxide) and acids in suspension. It cleans the engine of these chemicals and build-ups, and keeps the moving parts coated in oil. Finally, engine oil minimises the exposure to oxygen and thus oxidation at higher temperatures. It does all of these things under tremendous heat and pressure.

A quick guide to the different grades of oil

Mineral or synthetic?

Mineral oils are based on oil that comes from dear old Mother Earth which has been refined. Synthetic oils are entirely concocted by chemists wearing white lab coats in oil company laboratories. For more info, see the section on synthetics further down the page. The only other type is semi-synthetic, sometimes called premium, which is a blend of the two. It is safe to mix the different types, but it’s wiser to switch completely to a new type rather than mixing.

Synthetics

Despite their name, most synthetic derived motor oils (ie Mobil 1, Castrol Formula RS etc ) are actually derived from mineral oils – they are mostly Polyalphaolifins and these come from the purest part of the mineral oil refraction process, the gas. PAO oils will mix with normal mineral oils which means Joe public can add synthetic to his mineral, or mineral to his synthetic without his car engine seizing up (although I’ve heard Mobil 1 is actually made by reformulating ethanol).

The most stable bases are polyol-ester (not polyester, you fool). When I say ‘stable’ I mean ‘less likely to react adversely with other compounds.’ Synthetic oil bases tend not to contain reactive carbon atoms for this reason. Reactive carbon has a tendency to combine with oxygen creating an acid. As you can imagine, in an oil, this would be A Bad Thing. So think of synthetic oils as custom-built oils. They’re designed to do the job efficiently but without any of the excess baggage that can accompany mineral based oils.

Pure synthetics

Pure synthetic oils (polyalkyleneglycol) are the types used almost exclusively within the industrial sector in polyglycol gearbox oils for heavily loaded gearboxes. These are typically concocted by intelligent blokes in white lab coats. These chaps break apart the molecules that make up a variety of substances, like vegetable and animal oils, and then recombine the individual atoms that make up those molecules to build new, synthetic molecules. This process allows the chemists to actually “fine tune” the molecules as they build them. Clever stuff. But Polyglycols don’t mix with normal mineral oils.

Mixing Mineral and Synthetic oils – new concept

The web is a great place to keep things up-to-date, so here’s the current thinking on the subject of mixing mineral and synthetic oils. This information is based on the answer to a technical question posed on the Shell Oil website.

There is no scientific data to support the idea that mixing mineral and synthetic oils will damage your engine. When switching from a mineral oil to a synthetic, or vice versa, you will potentially leave a small amount of residual oil in the engine. That’s perfectly okay because synthetic oil and mineral-based motor oil are, for the most part, compatible with each other. (The exception is pure synthetics. Polyglycols don’t mix with normal mineral oils.)

There is also no problem with switching back and forth between synthetic and mineral based oils. In fact, people who are “in the know” and who operate engines in areas where temperature fluctuations can be especially extreme, switch from mineral oil to synthetic oil for the colder months. They then switch back to mineral oil during the warmer months.

There was a time, years ago, when switching between synthetic oils and mineral oils was not recommended if you had used one product or the other for a long period of time. People experienced problems with seals leaking and high oil consumption but changes in additive chemistry and seal material have taken care of those issues. And that’s an important caveat. New seal technology is great, but if you’re still driving around in a car from the 80′s with its original seals, then this argument becomes a bit of a moot point – your seals are still going to be subject to the old leakage problems no matter what newfangled additives the oil companies are putting in their products.