Engine oil is the lifeblood of your car. It lubricates your engine parts, keeps things cool enough not to succumb to the awesome friction and heat that your car is going through when you’re using it, and ensures that you get mile after mile of smooth and pleasing operation.
The problem is that in doing its job, oil becomes contaminated and full of nasty debris that makes it increasingly viscous and unable to perform its duty within the engine. When it gets to that point, it’s time for an oil change. Thankfully oil changes tend to be a reasonably priced service , so it won't kill the bank either way and they pack a big bang for your buck.
The question is, how often should you change your oil? Is it the same for all types of oil? Is the commonly understood “magic number” of 3000 miles still valid? All these questions and more we will be exploring in today’s blog.
Background: Types of Engine Oil
Let’s first be clear on the broad types of engine oil that there are out there in the marketplace today. People might have different ways of dividing the categories up more precisely, but there are 4 broad categories that are easily identified within the world of engine oil:
Conventional Engine Oil
Conventional engine/motor oil comes in a wide range of viscosities and quality ratings. It has long been used as the go-to motor oil for the average hatchback, sedan or wagon with no particular complexity or unique quality to the engine. It was long the choice of the non-specialty engine, like a “default setting.”
Where conventional oil is refined from natural crude oil, synthetic oil is that which has been chemically engineered and processed to perform some specific functions. Mostly, they are engineered to work more efficiently than normal oils and to boast better protective and anti-corrosive properties. It’s also far more effective at high and extreme temperatures than regular oil. It is oil for those engines that reach various extremes and need oil that has the special additives and protections that specialty engines require.
Synthetic Blend Oil
Blends use a mixture of conventional base oil with some synthetic additives to create some particular resistances or other necessary qualities. At their heart, they are conventional motor oil, but they contain a hint of the synthetic which, for instance, allows it to protect an engine against oxidation.
Finally, we have high-mileage oil which is formulated for vehicles who have already completed 75,000 miles or more in their lifetime. It typically contains additives that are designed to cut down on problems like oil burn-off, oil leaks, and other things that commonly occur in older and “more experienced” engines.
Oil Viscosity and Other Designations
If and when you find yourself buying engine oil, you might be dumbfounded by the series of letters and numbers, as well as apparent symbols, badges and other labels that appear on the packaging. Let’s just demystify some of that before we move on to the question of when it’s time to get oil changes.
First of all, there’s the oil viscosity, which is important. If you’re using conventional oil that comes in different viscosities, you’ll often make a choice based on climate. If you live in a cold climate, you need low-viscosity oil that is “thinner” and therefore flows more easily. Cold makes it harder for thicker oils to move freely between the many parts of the engine. The numbers on the oil container you have in front of you will tell you the viscosity.
The ratings are created by the Society of Automotive Engineers (SAE). A typical rating might read SAE 15W-40, for instance. The “W” stands for winter. The number 15 before the W indicates the cold-temperature viscosity rating, and the 40 at the end is the high-temperature viscosity rating. Lower W numbers are better in winter because they flow better in colder temperatures.
Another addition on the packaging to look for is the API and/or ILSAC label. These show that the engine oil meets the minimum industry standard. It’s not unlike seeing an FDA-approved label on a medicine packet. API stands for the American Petroleum Institute, and ILSAC for the International Lubricant Standardization and Approval Committee. Look for these labels to help ensure you’re getting a quality product.
How Often to Get an Oil Change: According to Mileage
The best thing to do if you’re wondering about the intervals between oil changes is to check the OEM-issued maintenance schedule, which you’ll find in your owner’s manual. That will typically give you a mileage marker to follow. There could be a time marker also, and the guidelines say to change your oil whichever of the markers --- mileage or time --- you reach first.
Your car may also be in the habit of telling you when it’s time to change the oil by indicating it with a dashboard warning light. Mostly those warnings indicate that there’s just something wrong with the oil --- or connected to the oil --- and doesn’t necessarily mean it’s time for an oil change.
If you consult the owner’s manual, it’s like to say either every 3,000 miles (older vehicles, especially from before 2010) or every 5,000-7,500 miles (newer vehicles post-2010). This has some relation to the type of oil people use, with older cars using more conventional engine oil and newer ones using blends and synthetic oils more commonly, which allow for greater intervals.
Besides the two we just mentioned, two more common recommendations are every 1,000 miles, and every 10,000-15,000 miles. These are obviously representing two bigger extremes. We’ll take a closer look at how often to get an oil change using each of these mileage recommendations to explain.
When you do decide to make the switch, you can often fit it into a quick trip during the work day so don't worry about not having your car for too long.
Every 3,000 Miles
Let’s start with this common recommendation for every 3,000 miles. Earlier in our blog today we mentioned 3,000 miles as a so-called “magic number” because it has long been held by mechanics, OEMs and anyone generally with some knowledge of oil changing that 3,000 miles was about the right interval. As with many things in an evolving industry, the number was founded in truth but has become somewhat outdated and irrelevant as technology continues to improve.
Anyway, many still adhere to the 3,000-mile interval, and if that is what your car owner’s manual recommends, then it’s a good idea to stick to that. It’s also a good interval if you only use your car for daily driving and rarely (if ever ) undertake long journeys.
As it happens, for those whose journeys are dominated by short trips, more regular oil changes are most likely required. We’ll cover more on that further below when discussing the 1,000-mile interval.
Every 5,000-7,500 Miles
This is the new growing consensus among mechanics, OEMs and the general hearts and minds of the driving public. It’s driven mostly by the increasing use of blended and synthetic engine oils that are more protective and durable even in spite of individual driving habits.
The need for oil changes with conventional engine oil, for instance, is greatly impacted by individual driving style and daily driving habits (see more below).
Therefore, if you see 5,000-7,500 miles as the recommended interval in your owner’s manual, then you can be safe in the knowledge that it is the correct interval. Also, depending on your driving habits and style, you might be able to use this interval even if the OEM doesn’t originally recommend it.
If you undertake a greater number of longer journeys at higher, steadier speeds, during which time the oil has a chance to boil off condensation that gets built up in the system, then your oil likely will last longer, even longer than it claims.
Every 1,000 Miles
Now, let’s turn to the extremes in terms of mileage and see why they exist. First of all, it may seem strange to suggest that you’d need an oil change every 1,000 miles. For some Americans, that would mean getting an oil change at least once a month.
With some experts now saying that every 3,000 miles is too frequent, how could there be a situation in which a need arises to change the oil after 1,000 miles? As we’ve suggested earlier, it’s mostly connected to individual driving habits.
First, if your daily driving routine is made up almost exclusively of trips of 10 miles or less and you are therefore frequently starting the engine, driving short distances at low speeds, stopping the engine, doing errands, getting back in the car, restarting the engine, and so one, then a smaller interval between oil changes is about par for the course.
Most of the wear and tear that a car’s engine undergoes happens when you’re starting the car. Furthermore, as we also touched on previously, driving short distances at low speeds means that the engine is not getting hot enough to burn off the condensation that builds up in the system, all of which contribute to your engine oil breaking down faster.
This is why the 1,000-mile and 3,000-mile intervals remain valid for some people, even regardless of what the OEM recommends. Your driving habits, as well as your local environment have a great bearing on oil performance. For example, dry and dusty environments will cause oil to accumulate grit and debris faster, which shortens the change interval. If you also drive a vehicle loaded up with heavy tools and equipment like a truck or van, then oil may break down faster.
For this reason, it’s hard for anyone to judge exactly for any car and driver which interval is best. Let’s now look at the other extreme.
Every 10,000-15,000 Miles
The other end of the scale is cars where even the OEM schedule recommends an oil change every 10,000 miles or more. How is there such a difference here? The chief reason is the use of synthetic oils, which we’ll get to in the next section.
If a car has a much larger recommended interval, then the most likely explanation is that it uses synthetic oil. However, driving habits also play a big part in the recommendation, as do local environmental and weather conditions.
How Often to Change Synthetic Oil
We mentioned already that synthetic oil comes with larger intervals between oil changes, but how definite are these? Let’s take a closer look at how often to change synthetic oil. The first thing to consider is whether the synthetic oil is a full synthetic or blended synthetic oil.
Blended synthetic oil will likely not last as long as full synthetic oil. Remember that blended oil is, at its heart, still conventional motor oil. It has been given certain additives to create some additional protective properties, but for all intents and purposes, it is still at least partly conventional oil. That means it won’t last as long as pure synthetic oil.
Why Does Synthetic Oil Last Longer?
The main reason for the disparity is the way in which synthetic oil is made. It is more refined than conventional motor oil, which means that friction is further reduced, the production of engine sludge and other contaminants that clog your oil filters is reduced, and the engine overall works better and is more protected.
That’s why the range of intervals for synthetic oil stretches from every 7,500 miles at the low end up to every 15,000 miles at the high end. Blended oils might last 5,000-6,000 miles depending on what kinds of additives have been put in, and what the individual driving habits and style of the driver are.
Conclusion: Signs That Your Need an Oil Change
Mileage is the most common indicator used for needing an oil change, as we have discussed. Each of these mileages can also become a timeframe. Every 1,000 mile or every 1 month; every 3,000 miles or every 3-6 months; every 7,500 miles or every 12 months, and so on.
However, we must also not ignore the many other signs that we are need an oil change, regardless of what our mileage has been since the previous one:
- Appearance of a dashboard warning light
- Excess black vehicle exhaust
- Increased engine noise
- Gritty and dirty oil texture --- it should be silky and smooth like caramel (check the dipstick)
- Engine is shaking when you are idling
- Falling oil levels in the engine --- there could be a leak, too
All of these signs must be observed because these can happen in between regular intervals and for reasons beyond regular wear and tear. It’s not an overstatement to say that oil is the lifeblood of the car’s engine. It’s therefore crucial to stay aware of when it needs changing.