Every day, we face some complicated decisions. Can I skip the gym today? How much of my paycheck should I save for retirement? How often do I need to change my car's oil? We can't help you with the first two, but knowing your oil change interval has become easier with modern cars. Let's take a look at what happens when you don’t change your engine oil, when you should do it, and what type of oil you should use.
The engine is the heart of every car or truck, and the oil is its blood. The purpose of the oil is to lubricate, clean and cool the many moving metal parts of the engine. Oil is circulated through the engine’s cavities by an oil pump, and a specific pressure has to be maintained for the engine to perform at its best.
But oil ages, and if it isn’t changed, your engine can experience premature wear from the buildup of dirt and debris. When oil gets old and dirty, it also loses its ability to protect against friction. The more friction that exists between moving metal parts, the more wear and the fewer miles you’ll be able to drive before your engine needs to be rebuilt or replaced.
Neglected oil maintenance can also cause a thick sludge to form in your engine that can block vital passages and cause engine failure. With many modern engines, oil pressure is also used with variable valve timing systems and to keep proper tension on the timing chain.
Many of today’s cars have oil life monitoring systems that tell you when it’s time for a change. These systems use factors like engine speed, temperature, miles driven and time to determine when your oil service is due. Before your oil change is needed, the car will begin to remind you with a dash light or message on your infotainment screen.
If your car doesn’t have this feature, don't worry. The owner’s manual has all the information you need to figure out when to change your oil. Many automakers will list a couple of different oil change intervals based on how you use your car. For example, a pickup truck that frequently tows heavy loads may have a shorter interval than a passenger car that's primarily used for highway driving. Many manuals will list the former as "severe duty" driving, and the latter as "normal" driving.
The 3,000-mile rule you’ve probably heard of used to be the gold standard. But unless you’re driving a car made before 1985 or so, it’s not true any more. For many years, vehicles were made with inefficient fuel delivery systems. This caused fuel to dilute engine oil, weakening its ability to protect engine parts. Because of this, most cars had a three-month or 3,000-mile oil change interval.
But today, with advances like fuel injection and positive crankcase ventilation systems, fuel is kept out of oil, dramatically increasing the oil’s life. The oil itself has changed in the past few decades, too, improving longevity. Most modern cars can go at least 5,000 miles between oil changes, and some cars can even go a whole year, or about 10,000 miles or more. But again, check the maintenance schedule in your owner’s manual. It has the most reliable information, and is likely a better guide than the sticker the mechanic puts in the corner of your windshield.
If you know someone who’s still cruising around in the old family Buick Roadmaster, then, by all means, they should stick to changing the oil every 3,000 miles. But for most of us, oil changes are needed a lot less frequently.
And if you have a car that you hardly ever drive — say, less than 3,000 miles a year — you should still get its oil changed once a year. This not only keeps the oil fresh and clean, but offers a chance for a mechanic to inspect the vehicle to see if anything else is going wrong.
The owner's manual will also list the proper type of oil and which weight to use. Some cars will need fully synthetic oil, while others are fine with less expensive conventional oil. The weight refers to the viscosity or thickness of the oil, and the owner’s manual may list a choice of weights based on the climate and conditions you drive in.
Although some manufacturers will recommend a certain brand of oil, it's far more important to pay attention to weight and type. Most major oil brands offer similar protection, but if you want to be sure it's a quality product, look for the API "starburst" symbol (shown here at right) on the container. This means the oil meets the standards of the American Petroleum Institute, which conducts quality tests on almost all major oils.
No matter which oil you use, remember to change the oil filter at recommended intervals, as well. Most carmakers require a new filter at every oil change because it’s the only way to keep oil clean between services. Changing the filter will also increase the lifespan of the oil, ensuring the best protection for your engine.
Most people lead busy lives, so it’s not always easy to make time for an oil change. We get it, and so does your car. Automakers plan that some folks will be a little late on getting their oil changed, so some leeway is built into the recommended interval. If your owner’s manual says to change the oil every 7,500 miles, your car won’t grind to a halt on the 7,501st mile.
But you should aim to get to the garage within a couple hundred miles of that mark. The longer you wait, the less effective your oil will get, which can cause premature wear and cost you a lot of money in repairs. It can be especially important to change your oil on time if your car is under warranty. Manufacturers can deny engine repair claims if scheduled maintenance isn’t performed on time.
This article was originally published by RepairPal here.