Welcome to the second step in the three-part process of improving your vehicle’s fuel efficiency. In this one we’re going to delve into the mind of your vehicle a bit. If you’ve owned a few automobiles you’re probably fairly aware that each has a personality all its own. It may share the same color, features, look, and name on the back as several other models, but only yours has the little quirks and tricks that you become accustomed to after driving it for a certain period of time. These quirks can be little, like a squeaky seat or a firm gas pedal, or they can be major like needing to cycle the key once or twice before starting. These are the quirks that it exhibits externally. We’re going to talk about the quirks it has internally.

It’s Just a Machine… Isn’t It?

Yes, it is. But even machines can have their preferences. It’s a lot like planting a garden. You may be growing the exact same crops in the exact same soil as your neighbor, but the choice of fertilizers, nutrients, and foods can make a huge difference in the outcome of each garden. Cars are the same way. What one may perform extremely well on, another may barely meet the lower end of mediocrity with. Finding the right tastes for your vehicle will not only enhance its performance, but it will save you cash in the long run.

What “Taste” Are We Talking About?

The most obvious answer here is, of course, fuel brands and grades; but it doesn’t stop there. Your other fluids can have an effect on your vehicle’s fuel performance as well. By this we mean engine oil and transmission fluid. Now please don’t think that you can simply change what particular type of engine oil or transmission fluid your vehicle requires; that’s never a good idea. If your vehicle calls for 5W-30 motor oil or Mercon-V transmission fluid, you need to stick with these types. That doesn’t, however, mean that all brands are the same.


Most people are familiar with the three numbers staring back at them from the gas pump: most commonly they are 87, 89, and 92 (or 93). These represent the grade of fuel you’re purchasing. Contrary to popular belief, your vehicle will not perform better on a higher grade of gas. The different grades of gas measure how well it will burn in certain conditions. Lower octane levels will combust easier when compressed. This makes it easier for a standard vehicle to get a clean burn from a regular octane (87) gasoline. The higher grades are made more for sports and high performance vehicles. Your vehicle’s manufacturer typically dictates which fuel your vehicle will run best on. It’s wise to stick with this recommendation for peak fuel efficiency.

Oil and Transmission Fluid

Using the wrong grade oil in your vehicle is a definite no-no. Oils are classified by weight. That doesn’t mean that one oil will weigh more than another when set upon a scale. It has more to do with the thickness and viscosity of the oil. Engineers recommend a grade of oil based on the tolerances and protection needed for a specific engine. Deviating from this grade can not only cause your engine to work harder and burn more fuel, it can lead to a loss of protection provided by the engine oil. This can lead to some very major repairs. The same can be said for the transmission fluid. The type of transmission fluid prescribed by the manufacturer is the only thing that will provide the protection and operation needed for peak performance and fuel efficiency.

So How Do I Know What Brand to Pick?

This is where the choices begin to mount up. Believe it or not, there is a major difference in engine oils, transmission fluids, and gasoline. Just because one is the same octane or weight as another does not make them equal. Different companies use different refining processes, different additives, and some even offer recycled products that have been through the mill once already. The only way to tell what your vehicle will perform best with is by trial and error. Phosphorus, zinc, wax, and Teflon are all additives that different companies use in their products. Any one of these additives can cause your vehicle’s fuel efficiency to change or parts to fail at a faster rate. This is because a certain amount of engine oil does get burned in the cylinders during compression. Take a few months and try different brands of gasoline and engine oil. Keep track of your fuel efficiency by keeping a log book in your car to write down mileage and gallons at fill-up. When you find the combination that provides the best numbers, you’ll know your vehicle’s taste.

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