Subscribe to a magazine

Synthetic Motor Oil - Grease Lightning? - Tech

Oils
Jordan May | Writer
Posted September 1, 2005

The Myths Behind Synthetic Oils

How many times have you found yourself staring blankly at the motor oil rack at your local auto parts store, unsure what to buy? The fact is, most people are still unsure whether choosing synthetic motor oil over petroleum oil is going to help or hurt the life of their engine. Many people, including some mechanics who ought to know better, have been misled by persistent myths that need to be addressed. Is it true that synthetic oil will void your warranty? Will switching your oil to synthetic cause engine leaks? Let's find out.

So, what is synthetic oil? Synthetic oils can be derived from several sources, but the most stable are derived from polyol ester bases. These bases are created in a laboratory. To make them, chemists must break apart the molecules that make up the various substances, such as vegetable and animal oils, and recombine the individual atoms to build new synthetic molecules. This process allows the chemists to actually fine-tune the molecules as they build them.

As a result, synthetic molecules are often much more stable than the original molecules. For example, most synthetic-based oil molecules do not contain reactive carbon atoms; this happens because carbon has a tendency to combine with other elements, such as oxygen, in order to make acids, which can become unstable at high temperatures. In a sense, synthetic oil bases are made up of purpose-built molecules. Much as in purpose-built race cars, they tend to be streamlined, with no unneeded ingredients or added bulk.

Chemists then add anti-wear additives to the synthetic polyol ester bases. The most common of these are zinc dithiophosphates, which are essentially combinations of zinc, phosphorous, and sulfur molecules. These combinations are extremely effective as anti-oxidant, anti-wear, and anti-corrosion inhibitors. They have good thermal stability, but must be blended in such a way that the ingredients react at the proper temperature. Other additives are then added to control rust and foaming until the oil meets with requirements for each application.

Now that we know what makes up synthetic motor oil, let's talk about the more popular myths heard around the campfire.

Myth: Synthetic Motor Oil Will Void A Manufacturer's Warranty.This is untrue in most cases. As long as your vehicle's viscosity and performance requirements as outlined in your vehicle's owner's manual are met, using synthetic motor oils will not interfere with warranty coverage. However, one exception would be in certain Mazda vehicles where a "Wankel" or rotary engine is used and it has been recommended to not use synthetic oils. To be on the safe side, always check with your owner's manual before regular lubrication maintenance.

Myth: The Cost Of Using Synthetic Motor Oil Is Too High.To attempt to curb this myth, we must discuss extended drain intervals. Extended drain intervals basically means extending how long you can go between regular oil changes. Most of the major automobile manufacturers in the United States recommend a regular lubrication change date of every 3,000 miles or three months, whichever comes first. Most synthetic oils claim a lubrication change date of 7,500 to 9,000 miles or six months, depending on your vehicle's condition and your driving habits. Let's assume that we agree your vehicle can go three times longer between oil changes running synthetic motor oil. Below is a simple breakdown of estimated annual oil changes between synthetic and conventional motor oils using a typical replacement oil filter. We are claiming that our test vehicle traveled 30,000 miles in the past 12 months and uses 5 quarts of oil per oil change.

Myth: I Am Already Running Conventional Motor Oil, So I Cannot Switch.As long as your motor oil meets with viscosity and performance requirements as stated by your automobile manufacturer, synthetic motor oil and conventional petroleum motor oil can be interchanged. Most people who are currently running petroleum-based oil are often wondering when the right time is to switch to synthetic oil. Most experts recommend waiting 3,000 to 10,000 miles with a new vehicle before changing, unless your vehicle comes factory prefilled with synthetic oil. This will help make sure everything has seated properly within your engine and will help with engine-oil consumption.

Myth: Synthetic Motor Oil Will Cause My Engine To Leak.The majority of engine-oil leaks are due to failure in engine seals and gaskets. All oils, either petroleum-based or synthetic, have additives added to help control seal swell, gasket shrinkage, and hardening. Properly changing your engine seals and gaskets will prevent them from deteriorating more quickly using whichever engine oil you choose. Synthetic motor oil does have a greater fluidity, which is a concern if your vehicle already has existing leaks. Keeping your vehicle properly maintained is crucial. If you're planning on switching to synthetic motor oil in a vehicle with more than 20,000 miles, it would be a good idea to have an engine flush performed to remove any remaining deposits left in your engine.

Myth: Synthetic Motor Oil Will Last Forever.It would be nice to have factual information informing us that this is true. What a relief on the wallet it would be! All motor oils will break down over time due to driving conditions, engine wear, harsh weather conditions, failure to properly maintain your vehicle, and so on. However, many experts agree that by topping-off your engine oil, some additives in the oil can be replenished. Changing your oil and oil filter properly will allow the use of synthetic motor oils to outlast non-synthetic-based motor oils.

Myth: Using Oil Additives Is Just As Good As Using Synthetic Motor Oil.As much as these types of products are hyped on television, most of them have been proven to cause more harm than good. One of the main reasons that most experts suggest staying away from oil additives is that your current petroleum- or synthetic-based oil already contains a very extensive additive package. This package is blended to achieve a specific formula designed to work best with your engine. Upsetting this balance can cause negative effects, such as seal failure and leakage.

Myth: Synthetic Motor Oil Causes Sludge To Occur.Synthetic oils resist the effects of high temperatures and oxidation better than their petroleum-based counterparts, making them more resistant to sludge. When high temperatures occur within an engine, your motor oil's lighter ingredients tend to boil off, making the oil thicker. Petroleum-based oils have complex minerals not found in synthetic oils that when exposed to extremely high temperatures can react with each other and form gums, sludge, and varnishes. Because of their higher flash points and ability to withstand greater evaporation loss during oxidation, synthetics are actually more resistant to sludge development. Two of the biggest causes of sludge come from your air and cooling systems. Ingested dirt and water dilution can be a problem to any oil, petroleum or synthetic.

Spending some time researching this has lead us to believe that synthetic motor oils are something to be considered when thinking about your next oil change. Are there more myths out there? Of course. Are synthetic oils better? The choice is yours. Generally, most synthetic motor oils will allow your vehicle to run better during very extreme weather conditions, show slightly cleaner engine internals, in some cases allow for extended fuel mileage, and should maintain at least double the life of your conventional motor oil. If you want the peace of mind in knowing you can wait a little longer than 3,000 miles between oil changes, or if you drive in severe weather climates, then maybe a synthetic-brand motor oil is for you. Give it a look at your next trip to the auto parts store and good luck.

OPERATIONAL
COST
SYNTHETIC OIL
(3 OIL CHANGES)
CONVENTION OIL
(10 OIL CHANGES)
Labor: $45.00 $150.00
Oil: $89.85 $149.50 ($2.99 per quart)
Filter: $17.97 $59.{{{90}}}
TOTAL COST $152.82 $359.40

Comments

Advertisement