An oil change is one of the most important things you can do for your car
Regular oil and filter changes are among the most affordable, and at the same time most important, scheduled maintenance services you can do to keep your vehicle running reliably for many years. Without proper lubrication, the combustion engine becomes little more than an expensive boat anchor.
Engines are made up of hundreds of moving parts that have to slide and spin against each other, and without a reliable supply of clean oil, those parts will grind to a halt before you get to the end of the block. In addition to its primary function of reducing friction between moving parts, engine oil also acts as an additional coolant to help take some of the combustion heat away from the cylinders.
To properly do its job, oil has to flow freely through dozens of passages in the engine. The larger passages are cast into the cylinder block and heads, while many smaller ones are drilled into crankshafts and piston pins. While oil does help minimize wear of bearings and other metal parts, tiny metal particles eventually contaminate the oil over time. A mix of unburned fuel and exhaust gases can also slip past the piston rings, mixing with the oil and diluting it.
If oil isn’t changed according the vehicle’s maintenance schedule, it will get thicker and turn into a sludge that can’t do the intended job. The oil filter, which helps to remove dirt and other particles from the oil, will also get filled up over time. When that happens, the pressure increases and a bypass valve opens that lets unfiltered oil run through the engine. If this happens for an extended period, it can cause very expensive damage.
Until about the mid-1990s, it was generally recommended that drivers get their oil and filter changed every three months or 3,000 miles. Since then, a number of technological improvements have allowed oil change intervals to be extended to 10,000 miles or more, depending on the make, model and powertrain of vehicle. Driving style, frequency of towing, and weather and road conditions also play a big role in how often the engine oil in your vehicle should be changed, so you should check your owner’s manual for guidance. Your dealer’s service technicians are also a great resource for recommendations that are personalized for your particular vehicle and driving conditions.
Oil formulations have improved, making oil more stable so that the thickness, or viscosity, doesn’t change as much over time, and detergents added to oil help break down contamination from fuel and exhaust. New fully synthetic and synthetic blends reduce engine friction and improve fuel economy while lasting longer.
Modern engine electronics also help to extend oil life. Most new engines have sensors that can detect the condition of the oil, and systems built into the electronic control unit monitor driving conditions. By keeping track of conditions like temperature, average speeds and engine loads, oil life monitors can determine if your vehicle is subjected to conditions that can accelerate oil break-down––like frequent or heavy towing; extreme heat; lots of stop-and-go driving––or if most of your driving is highway cruising.
Vehicles equipped with oil life monitors provide an indication of oil condition in the instrument cluster and recommend when to get an oil change. Vehicles that are subjected to more stress might be recommended for an oil change every 3,000 to 5,000 miles, while those that see lighter duties might go a little more, saving money and time for the driver.
Speaking of saving time and money, while it’s not difficult to change oil yourself at home, the hassle of cleanup and properly disposing of the old oil (never dump it on the ground or in a sewer) can be avoided by having your oil changed by your dealer. As part of your dealer’s oil and oil filter change service, service technicians will also lubricate key chassis components, top off fluids as necessary, inspect other vehicle systems and discuss with you any problems or questions you may have.
A small investment in maintenance will keep your vehicle running reliably for many years to come, and will also save you money at the pump.