Oil Change Time Vs Mileage – What to Use for Oil Changes?

At the early stages of this pandemic, driving went down by around 48%. How does the current condition impact your oil change schedule? Oil change time vs. mileage – what to use for an oil change in this situation?

Both time and mileage degrade your car’s engine oil. So, it is also essential to change the engine oil if it has reached its maximum time and not just its maximum mileage. The usual recommendation is to change oil every three to six months or 3,000 to 5,000 miles. This equates to about two times a year as the minimum.

The recommendation is to schedule change oil every 3,000 miles in the past. However, modern lubricants are formulated so they can last longer. So, today’s advice is to change oil every 5,000 to 7,000 miles.

Read on to learn more about what you can use as your basis for your oil change schedules, whether time, mileage, or both.

Oil Change Time Vs Mileage

oil change time vs mileage

Over Time the Oil Degrades

The oil that lubricates the internal components of your car’s engine is subject to degradation. The total mileage you have driven and the length of time affect the engine oil’s quality and service life. So, it’s not a simple question of oil change by time vs. mileage.

Schedule Change Oil Every 3,000 to 5,000 Miles Or Every Three to Six Months

The recommendation is to schedule an oil change every 3,000 to 5,000 miles or every three to six months. You can still stretch this time using a full synthetic oil. This oil could last even as far as 15,000 miles. That also means its maximum time is also extended considerably.

Both Time and Mileage Affect the Oil’s Lubricating Capacity

Should you change the oil after a certain period or after you reach a certain mileage? Most engine oil manufacturers indicate the words at the end of their warranty statement: “whichever comes first.”

Does that mean the impact of time and mileage on the oil are the same? The experts who developed the engine oils’ formulas considered oil change by mileage vs. time. They believe that both time and mileage affect the lubricating capacity of the oil they make.

Perhaps they have used actuarial systems of computation to arrive at that concept of “whichever comes first.”

If the engine oil can last 5,000 miles or six months, you need to change it if you are regularly driving for six months, even if your odometer reading has not yet reached 5,000 miles.

Full Synthetic Oil Change Mileage

The limit of 5,000 miles or six months was in the past. Today, engine oil manufacturers have improved their formulation that they are now bold enough to predict that their engine oils can last up to 15,000 miles before they require changing. This is the full synthetic oil change mileage.

These are full synthetic oils. In the past, you had to change the oil every six months; now, you can schedule your change oil every one and a half years. That’s because 15,000 miles is three times 5,000 miles.

Change the Full Synthetic Oil After One and a Half Year

But it remains that even if your odometer reading has not yet reached 15,000 miles, and yet the oil inside the engine has been there for about one and a half years, you ought to change it soon – if you want your car running smoothly as before. It is not just a question of oil change by time or mileage.

You need to understand that both time and mileage affect the properties of engine oil. That is why oil change schedules are based on mileage and time intervals. Experts know that over time the engine oils degrade.

It’s just natural that all products have their shelf lives. Experts designed them so that the point by which the oil becomes useless is longer than their shelf lives. They have computed the number required to predict the oil’s decay rate.

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What to Use: Mileage or Time?

Your car’s manufacturer most likely has listed a time-based and mileage-based oil change schedule in the operator’s manual. Usually, it is every six months or every 5,000 miles. They probably stated that you should change the oil, whichever of the two comes first.

If you have been changing the oil based on the mileage, you can continue with this practice as long as you reach the maximum mileage before reaching the maximum time. But depending on your oil change schedule purely on miles alone is not good for your engine.

You see, engine oil, even if it is not used, degrades with time. So, it is also essential for you to change the oil if it has already reached its maximum time limit, even if your car hasn’t clocked in the maximum miles yet.

The general recommendation is to have an oil change every 5,000 miles or every six months, whichever comes first.

If you have a newer vehicle, you are not required to change the oil as frequently as an older vehicle. The point is: that you need to use both time and mileage in scheduling oil changes. They are not exclusive of each other.

And if your newer car uses full synthetic oil, you can use it even longer than conventional engine oils. Even then, you should check the oil once a month, at the very least. You need to check its level and its condition.

Time or Mileage – Which Is More Important?

oil change time versus mileage

Should you change your oil based on time or mileage? This is a debatable question. Some think the mileage is more important than time. Others disagree and say time should have the first consideration. Which of the two is right?

A Car Cannot Record How Long the Engine Is Running

As one person said, time is the hours the engine is running. They say this is why aircraft engine wear is given in hours run instead of miles flown. But cars do not have fine instrumentations like those found in airplanes.

Cars are not capable of keeping a record of how long you drove them since your last oil change. What cars have are odometers that record their mileage.

Unused Cars Still Wear Out

You should also understand that the engine and its internal components are wearing out, whether it is just sitting in your garage, running a few miles on city streets, or breathing heavily at accelerated speeds on the highway. It is the same with the engine oil.

Have a Regular Schedule of Oil and Oil Filter Changes

So, even if your car sits for long periods without covering hundreds of miles each year, you should still have a regular schedule of oil and oil filter changes. Oil degrades no matter what, so you should change it at least yearly.

Change Full Synthetic Oil At Least Once a Year

Full synthetic oil gives the best engine protection. However, you still have to change it at least once a year.

For instance, you still have to change Red Line oil, a full synthetic oil rated for every 15,000 to 17,000 miles once a year. This is if you have not reached the maximum miles yet.

Time and Mileage Are Both Indicators of When to Change Oil

As it is becoming clear, you can see that both time and mileage are important indicators of scheduling an oil change.

There may be conflicting opinions about the length of the intervals. But the fact is obvious: engine oil degrades with the mileage driven and by the length of time it sits inside the engine.

Regardless of which comes first, you must change the oil. It’s not safe to think that since you have not yet covered the appointed miles, you can still stretch the use of the oil.

Unfortunately, many drivers think this way. They don’t usually think about when the oil is sitting there doing nothing. It still degrades even if it is “wasting its time.”

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How Often to Change Oil

If you will honestly look at it, scheduling oil changes depends on who gives the recommendations. This is one of the causes of confusion.


For instance, Quick-lube says you must change it every 3,000 miles. Car manufacturers say it should be every 5,000 to 7,000 miles. But synthetic oil manufacturers claim that it should be 10,000 miles. Who’s right?


Edmunds.com, a car review website, says that the exact answer depends on your particular driving patterns more than anything else.

Those who don’t exceed 10 miles in their driving and start their engines frequently when the oil is cold should change their engine oils more often. It says twice a year at the very least.

Why did Edmunds.com say this? If you don’t do much driving, the oil does not get hot enough to cause the evaporation of its moisture condensates. And when you start your car often when the oil is not hot, you will cause more engine wear.

But when your daily drive is no less than 20 miles, mostly on flat freeways, you can schedule your oil changes according to the car manufacturer’s recommendation.

As your car ages, it will require more frequent oil changes. But that is a general rule. You should still consult a qualified mechanic to be sure.

TrustMyMechanic Website

The 3,000-mile oil change requirement is a myth, says Austin Davis of the TrustMyMechanic website. Davis believes that car owners do frequent oil changes because of the economics of the oil industry.

He also believes that car owners were sold to the idea of having ‘cheap insurance’ against engine issues that may crop up, no matter if they need the oil change or not. He gave the example of Jiffy Lube, one of the biggest chains of stores offering oil changes.

Pennzoil, an engine oil brand, owns Jiffy Lube. Pennzoil sells as much engine oil as possible to as many car owners as possible.

Switch to Full Synthetic Oil

If you don’t want these frequent oil changes, switch to full synthetic oil. You can reduce your trips to the car service centers and save money. Full synthetic oils last much longer than standard engine oils. They also perform better than petroleum-based engine oils.

While it is more costly than standard engine oils, full synthetic oil can last three or more times longer. Davis believes that synthetic oils can last from 10,000 to 15,000 miles, equivalent to six months or more.

For example, Red Line, NEO, and Amsoil can last up to 25,000 miles. That is equal to one year before you need to change the oil. If you use these oils, perhaps you change the oil every two years at the maximum.

Again, should you get an oil change based on time or mileage? In the past, it was a common practice to change the oil after 3,000 miles, but due to improved formulation, you can now schedule an oil change after 5,000 to 7,500 miles. If your car has a full-synthetic motor oil, you can change the oil after 15,000 miles.

Which Matters Most: Time or Mileage?

oil change time or mileage

It Depends

The answer to this question is: it depends. If your usual driving mileage is low, you should base your oil change schedules on the length of time the oil has stayed inside the engine. But if you are driving hundreds of miles every week or every month, you should base it on your accumulated mileage.

It may seem logical to postpone your oil change since your driving miles are still far from the limit. However, it may be counterproductive if it’s already past the recommended time because of engine oil composition.

Engine Oil Acts as a Lubricant and Coolant

The engine oil acts primarily as a lubricant. But it also acts as a coolant. It pulls very small metallic particles from the wear and tear of the engine into the oil filter and boils off hazardous chemicals produced by combustion.

If you do not drive frequently, these small particles and harmful substances will remain in the oil.

Follow the Oil Change Recommendations Religiously

So, you need to follow the oil change recommendations religiously. This will result in a trouble-free operation of your car’s engine, transmission, and other critical parts. It will also ensure full warranty coverage of your car.

Another thing that matters in this context is your driving pattern. Does it fall under normal or severe? If your usual driving takes you to rough roads and extreme climates, you are driving in severe conditions.

If you are doing lots of stop-and-go driving, idling now and then, towing a trailer, and driving in cold weather, your driving pattern can be considered severe.

Oil Change for Old Car vs. New Car

Oil change schedules also depend on whether the car is old or new. As I’ve mentioned earlier, other factors also influence the schedule, such as the driving conditions and the type of oil used:

Old Cars

If you have an older car, its oil change schedules will be mostly based on the mileage. Additionally, there will be two schedules, one for normal operation and another for severe driving conditions.

You will fall under the ‘severe’ category if you have the following driving conditions:

  • In dusty and extreme cold or hot conditions
  • If you are towing a trailer or you are carrying heavy loads
  • In continuous stop-and-go driving
  • In short trips of around five miles or less

If you fall under these conditions and your car is older, you should have a more frequent oil change schedule. But if you fall under the normal driving category, you can settle for the oil change schedule of the car manufacturer or the engine oil maker.

New Cars 

Oil-life Monitoring System

If your car is a later model, it may already have an oil-life monitoring system. This feature can determine when you need to change the oil. It will also give you an alert signal on the dashboard.

Analyzes the Car’s Actual Operating Conditions

Compared to older mileage and time-based systems, this system uses advanced tech that analyzes your car’s actual operating conditions to determine the time or mileage that the oil begins to deteriorate.

Eliminate ‘Severe Service’ Recommendations

This oil-life monitoring system enables modern cars to eliminate ‘severe service’ recommendations since it automatically reduces the oil change interval when it detects heavy-duty or severe operations.

Reset the System After an Oil Change

The lube technician will reset the system whenever you have an oil change. You could reset this system if you were the one who was changing the oil. Just follow the instructions prescribed in the car’s operator’s manual.

Frequently Asked Questions

Reading the following frequently asked questions will help you better understand which is best to use, time or mileage, in scheduling your change oil:

Should I Base My Oil Change on Time or Mileage?

It depends on which comes first. The engine oil’s consistency and lubrication properties deteriorate, even if not used regularly. So, there’s a reason why oil manufacturers always use the caveat: ‘whichever comes first.’

The 3,000 to 5,000 miles or six months is based on normal driving conditions. But since we don’t always drive in normal driving conditions, these parameters should not be the sole determination of your oil change schedule.

Should I Factor Time in My Oil Change Schedule?

You should consider time, especially if you are not driving your car regularly. If the recommended time is fast approaching and you haven’t yet reached the recommended mileage, you should not try to extend the use of the oil.

After its recommended time, the oil’s ability to lubricate your engine is reduced. It needs to be changed.

Can I Schedule Change Oil Every Two Years?

It is not safe for your car to extend the life of its engine oil to two years. The best is one year or a little over using full synthetic oil.

But if you are using conventional petroleum-based oil, the most you can use it is six months. And then again, it will also depend on your driving category.

Conclusion: Oil Change Time Vs Mileage

Both time and mileage impact your schedule for oil changes. They both degrade the quality of engine oil. So, you must change the oil once it has reached its maximum time.

Generally, it is recommended that you change the oil every three to six months or 3,000 to 5,000 miles. That is equivalent to around twice a year as the minimum.

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