Why you need to get an Oil Change

One of the many services that we offer here at Big Brand Tire and Service are oil changes. This includes the draining of the old oil, the replacement of the oil filter, and filling up with new oil. Every car has its own requirements for what type of oil should be used as well as the interval at which the oil must be changed. Engine oil provides three key functions in a modern internal combustion engine:

  • It keeps engine components working smoothly together.
  • The inside of an engine, a place where there are thousands of controlled detonations happening every minute, can be a hot place, and oil helps draw heat away from the combustion chamber.
  • It prevents carbon and varnishes from accumulating in the engine.

Eventually, as the oil gets dirtier and dirtier, it will stop lubricating and the engine will quickly wear and fail. Dirt will accumulate in the oil. The filter will remove the dirt for a while, but eventually the filter will clog and the dirty oil will automatically bypass the filter through a relief valve. Dirty oil is thick and abrasive, so it causes more wear. Also the additives in the oil, like detergents, dispersants, rust-fighters and friction reducers, will wear out; so the oil won't lubricate as well as it should.

Understanding Oil Viscosity and Climate

There are many different weights of oil, such as 10W-30, 5W-30, and 0W-20 being some of the more popular. These different oil types are referred to as different viscosities. Viscosity, put very simply, is a fluid's resistance to flow. Typically it is notated with the common “XW-XX." (example: 5W-30) The number before the "W" (winter) rates the oil's flow at 0 degrees Fahrenheit. The lower the number here, the less it thickens in the cold. So 5W-30 viscosity engine oil thickens less in the cold than a 10W-30, but more than a 0W-30. An engine in a colder climate, where motor oil tends to thicken because of lower temperatures, would benefit from 0W or 5W viscosity. A car in Death Valley would need a higher number to keep the oil from thinning out too much. Another factor that comes into play is the advancement of engines in the last decade or so. As engines become more and more precise, there is less of a need for thicker oil, and an increase in demand for thinner oil. For this reason a newer car is more likely to call for thinner (0W-20) rather than thicker (10W-30) oil. The second number after the "W" indicates the oil's viscosity measured at 212 degrees Fahrenheit. This number represents the oil's resistance to thinning at high temperatures. For example, 10W-30 oil will thin out at higher temperatures faster than 10W-40 will. The owner's manual provided by your vehicle’s manufacturer will recommend the ideal viscosity range for your car.

Oil Types

Next, we need to determine whether your vehicle requires conventional or synthetic oil. Typically if your car started with conventional, stick with it. If it first used synthetic, be wary about switching to conventional.

Types of oil - oil change infographic
  • Conventional Oil:

    Conventional oil is one of the most popular types of oil in that it is the cheapest, and standard in many older vehicles. However there is a downside to conventional oil. Conventional oils have a level of insoluble natural contaminants (paraffin, waxes, silicon, dirt). Under certain conditions these substances can form deposits inside the engine. Another result is that it is more likely to break down at high temperatures than the synthetic options. Being an impure substance, conventional oil is made up of molecules that are all different lengths. This means that there are small, medium and long hydrocarbon chains. The problem with conventional oil is that those short, lightweight hydrocarbons tend to burn off when they get hot. This causes the oil to thicken the longer it’s in an engine.
  • Full-synthetic Oil:

    Synthetic oil is becoming increasingly popular in higher tech engines. They are typically synthesized, which means they are pure from the get-go, containing no undesirable contaminants. They’re also more stable at a variety of temperatures. Because it is a synthesized oil, it is made with only medium-length hydrocarbon chains, which means it is a much more consistent oil that will not get thicker as it is used. This also means that it will flow better at low temperatures.  Additionally synthetic oils also handle high temperatures better than conventional. They’re better at transferring heat, meaning synthetic oils can actually help a vehicle’s engine run cooler. Of course the benefits of synthetic come at a price. They’re usually several times more expensive than the conventional oils. But with longer drain intervals (because they it will not break down or shear) and a potential increase in fuel economy, the benefits of synthetic oil justify the expense.
  • Synthetic-blend Oil:

    A Synthetic blend oil is essentially part conventional oil and part synthetic. It is formulated to offer better protection during heavier engine loads and the higher engine temperatures that come with it. These oils are popular with pick-up and SUV drivers because they do offer better protection, but usually cost less than full synthetic oil.
  • High Mileage Oil:

    A high mileage oil change is a special chemical blend of oils and additives available in a variety of viscosities. The biggest difference from the other options (High performance, Extended performance, etc.) is that high mileage has more seal conditioners in the formula. In essence it contains a ‘lotion’ that will help moisten any cracks in the seals, reducing the leakage of oil. It will also help make seals more flexible and can cause them to expand slightly, which will also help stop leaks. As a result there will be less oil leakage from the vehicle.

How often to get an Oil Change:

Oil plays a critical role in engine operation. Pumped through the engine under pressure, oil forms a thin film between all of the moving surfaces inside an engine, creating a physical boundary that prevents metal surfaces from touching. As time passes the oil becomes contaminated with byproducts of burning gasoline, reducing its effectiveness at providing that lubricating layer. It also accumulates small particles which can cause sludge in your engine and if left long enough can cause your engine to seize. This is why it is always important to follow the manufacturer’s recommendations and perform oil changes within the intervals required in the vehicle’s instruction manual. The standard recommendation is to get an oil change every 3 months or 3,000 miles. However, many kinds of driving conditions put a vehicle under the severe conditions category, and thus require oil changes more frequently. Severe service conditions can include, among other things:

  • Trips of less than 10
  • Driving in cold weather
  • Idling for extended periods
  • Stop-and-go traffic
  • Pulling trailers/carrying heavy loads
  • Driving in dusty conditions

As a rule of thumb, it is always safe to follow the manufacturer’s recommendations as found in the instruction manual.