When should I change the oil filter? Always change the oil filter with every oil change using a name brand filter. Oil filters are very inexpensive protection from internal engine contaminants. Under no circumstance would I deviate from this rule.

What kind of motor oil should I use? Our recommendation is to use a quality 5W30 or 10W30 API rated SJ, CG4 EC-II oil in modern gasoline engines.

Say what? … Let me explain what all this means.

The American Petroleum Institute (API) service symbol known as a “donut” can be found on the oil container. It is the source that provides information about engine oil. The symbol is divided into 3 parts.

At the top of the symbol is the oil’s performance level for gasoline and/or diesel engines.

The letter “S’ followed by another letter (such as SJ) indicates the oil is appropriate for use in a gasoline engine. SJ oils currently meet the highest standards for gasoline engines. A SG rated oil would meet a lower standard for gasoline engines.

The letter “C” followed by another letter and/or number (such as CG-4) indicates the oil is appropriate for use in diesel engines. CG-4 oils currently meet the highest standards for diesel engines. A CD oil would meet a lower standard for diesel engines.

At the Center of the API Service symbol is the oil’s viscosity. An oil’s viscosity, simply stated, is how thick the oil is.

There are two types of SAE classifications: Single-grade and multi- grade. A single-grade oil such as SAE 30 performs as a 30 weight oil in all weather conditions and is generally not recommended for cold weather use.

A multi-viscosity oil such has 10W30 has different characteristics according to it’s temperature. The 10 in 10W30 shows it performs like thinner 10 weight oil at cold temperatures. The W stands for winter and shows that the oil is appropriate for winter use. The 30 shows that the oil performs like 30 weight oil when hot. Therefore a 10W30 oil can be used across a broader range of temperatures than a single-viscosity oil can

At the bottom of the symbol, look for an Energy Conserving (EC) rating on your choice of oil. An EC-I oil offers up to 1.8% improvement in fuel mileage. An EC-II oil offers up to a 2.7% increase in mileage. Thicker oils will not likely have this rating.

We should always use an oil that protects the engine within the temperature range we live in. In this climate 5W30 and 10W30 oils are appropriate for year round use. These oils will protect your engine better than a single viscosity SAE 30 or a thicker Multi-Viscosity 20W50 oil will. I know putting a thinner oil in your car may go against everything some of you have been taught. First you must understand what motor oil is supposed to do.

For those who believe thicker is better, here are a few things to think about:

Motor oil is used to provide lubrication between moving parts to keep them separated and reduce wear. Most internal engine tolerances can be measured in thousandths of an inch, many times the space for oil to flow is no thicker that a human hair. Do you honestly believe that oil that flows like molasses will do a better job?

Oil is used to flush small metal particles from engine bearings and cylinder walls inside the engine. Would you use molasses for this purpose?

Oil is used to absorb heat from internal engine parts and carry it away. Inside an engine metal surfaces can be rubbing together 50 or more times a second. We need to keep a continuous stream of oil running through and over the surfaces to carry the heat away. Will molasses do the trick?

It has been proven that 90 to 95 percent of all mechanical engine wear occurs in the first 10 seconds of a cold engine start up. Cold starts easily equal hundreds of miles of warm engine wear. Is molasses going to get to the surfaces needing lubrication first?

I used molasses in the above examples to give you an idea of how thicker oils tend to flow at low temperatures. Many actually do become that thick when cold. Even when hot, thick oils will not flow as easily through the close engine tolerances where they are needed most.

There are a few instances where a higher viscosity oil will prolong engine life on high mileage and diesel engines. My best suggestion here is to consult a qualified mechanic before changing grades.

Should I use synthetic oil or conventional oil? The choice is again yours. Synthetic oils are superior to conventional oils in two important ways. They flow at lower temperatures and they can handle higher temperatures without breaking down. Some oil manufacturers claim that you can also extend your oil change interval when using their synthetic oil. I do not totally agree on this point. Although synthetic oil in general will retain its properties longer than conventional oil, it will still have to absorb all of the contaminants encountered inside your engine. It should therefore be changed at about the same frequency as conventional oil. The claim of a 25,000-mile oil change interval from one synthetic oil manufacturer was ridiculous as far as I am concerned. If I lived in an extremely hot or cold region, I would consider using synthetic oil on a regular basis. When you take into consideration the expense of synthetic oil, most will agree that using a quality conventional oil makes the most sense in this area.