When Should You Get an Oil Change? At 5K Miles or by Engine Time?

There’s a problem, however: when should you get an oil change, realistically? Are car manufacturers simply playing on our collective intelligence (just like the ‘life time tranny fluid’) or is changing engine oil by mileage the gold standard in the business of keeping an engine running clean?

As I sat in traffic today with the vehicle idling for many minutes, a thought struck me: this engine oil change metric according to miles is fundamentally defective and in extreme cases, is likely to cause more harm than good, if you live or commute in traffic-prone zones or generally, idle your engine a lot.

Today, I’ll show you how this pans out and, importantly, I’ll share with you how you can, alternatively, change your engine oil using a superior metric called ‘Engine Time’, ET.

Things are going to be extremely strange if you haven’t thought about them in the manner I’m going to explain. But, don’t worry: I’ll make it as simple as possible.

First things first, though: what does the 5k (or 7k or 10k) mile oil change mean?

5k Miles Means 5k Miles Driving on The Road!

The concept of 5k miles for oil changes means 5k miles when the vehicle moves, which makes sense (at least, on face value).

This is why, in the owner’s manual, there’s an express injunction to start the vehicle, engage it in drive, and start driving, almost immediately, being easy on the gas pedal until such a time when the engine and transmission fully warm up and both reach operating temperature.

The logic, as can be seen, is simple: the manufacturer is eager to have you actively avoid racking up time not covered by actual movement (which is likely to be missed).

However, this only mitigates the issue (of knowing when to change engine oil), as it is , it doesn’t completely solve the problem.

So, if it doesn’t, what does?

Do Not Change Your Engine Oil According to Mileage: Do This Instead

Instead of relying on good old mileage to change your engine oil, switch to Engine Time (E/T) , which is a record of how long the engine has been on, in a cycle. 

What this little counter on the instrument cluster does is that once the engine fires up, it starts counting, and whether or not you move, it continues its duties, so long as the motor runs.

This makes perfect sense since engine oil keeps circulating/degrading and never stops, even when you idle or are stuck in traffic.

How to Keep Track of Engine Time as an Oil Change Indicator

As much as keeping track of engine time as an oil change indicator is preferred to miles logged, it’s much more challenging to keep this record and tally things up when it’s time to change the oil.

This is for the following reasons:

1. Most older vehicles do NOT have this function.
2. This is a temporary memory-based metric; anything that plays with the starter battery distorts it.
3. Once it reaches 99 hours, it resets back to 01.

To avoid these challenges, assuming your vehicle has this function, simply log things down once ‘99’ is hit and a reset occurs, and then, tally everything up at the weekend — or month-end, whichever is preferred. 

Some vehicles, such as modern Hondas, have a sort of engine oil ‘health’.

This system uses a myriad of metrics to determine when your engine oil is due , and this includes miles logged.

Interestingly, one of the metrics used for this purpose also includes the time the vehicle remains ‘online’, E/T (Engine Time), as this ‘health’ depletes even when the vehicle is stationary.

If you use a modern Honda, you don’t need to bother with either your mileage or engine time: just stick to the recommendation and you’ll be fine.

How Many Miles Is an ‘Hour’ in Engine Time?

There’s another challenge that presents itself with this system of relying on engine time to change engine oil and not actual mileage covered: how many miles is an hour?

This is challenging , but largely depends on your driving reality (once you have this figured out, everything else falls into line).

If you drive in a busy city exclusively and idle a lot, an hour translates to 20–40 miles with an average of 30 miles.

If you drive exclusively on the freeway, an hour translates to 60–80 miles with an average of 70 miles.

If you do a healthy mix of city and highway driving, an hour translates to 40–60 miles with an average of 50 miles.

Note that the above are fair estimates that may vary widely, depending on your unique case and driving habits, so this should be taken for what it is: fair estimates.

So, assuming you drive a healthy dose of city and highway driving, 5,000 miles (suggested OCI interval)/50 miles (average miles covered in an hour of E/T) = 100 hours of engine time (E/T).

In such a condition, changing your engine oil should be done at 100 hours (or six months , assuming this is what your manufacturer recommends), whichever is first.

What About the Time Factor?

Once in an engine, engine oil degrades , whether used or not. 

For this reason, it makes sense that the six-month interval (or whatever your manufacturer recommends) be held sacred (this doesn’t cover Extended Performance engine oil formulations like Mobil 1 or Castrol, which can both hold up to the 12th month).

FAQs

I’ve done my best to answer the question of when it’s right to get an oil change. Manufacturers, remember, will often offer what appears to be the easiest way out of a challenge, provided it will sail through the warranty period, offer them good profit, and maybe, stand firm for a ‘reasonable’ time after the warranty cover is out.

That said, there may be some very important points that I may have missed. Conversely, you may have also missed some salient points while reading.

Since one (or all) of the above is true, this Frequently Asked Questions (FAQs) will smartly fill in the gaps.

Conclusion: When Should You Get an Oil Change?

The process of logging your E/T manually to determine when your oil change period is due is superior to the conventional system of relying on mileage in the sense that it (actually) covers the time the vehicle is on , not just when it’s moving (something the ‘mileage system’ does not). 

This accounts for idling and traffic situations, situations that are very hard on the engine and, unfortunately, are not conventionally considered when the business of changing engine oil comes up.

Don’t fool yourself, however: manually logging your E/T is hard work and requires some level of dedication for it to work.

However, if you’re serious about making sure that your engine lasts the longest, then this method is a no-brainer and a considerably small price to pay. 

You’ll also agree that answering the question: when should you get an oil change? become simpler…

…and to the point: when the hours are clocked!

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