Debunking 7 Myths About Engine Oil You Should Know About

Motor oil may seem simple. It's slick, it’s dark, and it's the lifeblood of your engine. But for many drivers in Montclair and nearby San Bernardino, what they think they know about engine oil could actually be doing their car more harm than good. There’s no shortage of engine oil myths floating around. 

Some get passed down from generation to generation.

Others come from outdated advice that doesn’t apply to today’s vehicles, like the Nissan Rogue, Kicks, or Frontier. Whatever the source, these common misunderstandings can lead to poor engine performance, costly repairs, and unnecessary stress.

In this blog, we’ll break down seven of the most popular motor oil myths. We’ll look at what’s true, what’s not, and what every Nissan owner needs to know.

If you’re unsure whether your vehicle is due for oil change services or you simply want peace of mind from a trusted team, the experts at Metro Nissan of Montclair are ready to help. Whether you're in Montclair, San Bernardino, or anywhere nearby, we invite you to stop by or contact us.

1. You Must Change Your Oil Every 3,000 Miles

This is probably the most common myth of them all. While this advice might have been true decades ago, it no longer fits with modern engines or advanced oil formulas.

Today’s vehicles, including the Nissan Kicks and Rogue, are built to go much farther between oil changes. Some can go 5,000 to 7,500 miles—sometimes even longer—with no issue. Always check your owner’s manual or speak to a technician to get the right schedule.

Why this matters:

Changing your oil too early won’t damage your car, but it can waste time and money.

If you're unsure about your oil schedule, booking a Nissan oil change appointment is the simplest way to keep your car on track.

2. Dark Oil Always Means It’s Dirty

It’s easy to assume that dark oil equals dirty oil. But that’s not always the case. Engine oil naturally changes color as it works. It collects heat, friction, and small debris, doing its job well. 

In many cases, the dark color simply shows that the oil is active and breaking down particles.

If you drive a Nissan Frontier in hotter conditions like San Bernardino, your oil might darken faster. That doesn’t always mean it’s time for a change.

Instead of going by color alone, check:

• Your oil level with the dipstick
• The oil’s feel (gritty vs. smooth)
• Your dashboard’s warning lights

Or just book a Nissan oil change to let a technician do the work for you.

3. Synthetic Oil Causes Leaks

This one sounds scary, but it’s not true for modern engines. Some older cars with worn seals might leak when switched to synthetic oil. But for newer models like the Rogue or Kicks, synthetic oil is not only safe—it’s often preferred.

Nissan engine oil is formulated to meet the needs of each model. Synthetic oil is cleaner, lasts longer, and performs better in both high and low temperatures.

If your engine leaks, it’s probably a worn part, not the oil’s fault.

4. Once You Use Synthetic Oil, You Can’t Switch Back

This is one of those engine oil myths that refuses to die. The truth? You can switch between conventional and synthetic oil. The key is using the right type for your engine. Nissan service teams may recommend synthetic oil for better long-term care, but switching won't cause damage as long as you’re using high-quality oil. 

That’s true for daily drivers like the Kicks as well as work-ready trucks like the Frontier. The only rule: never mix different oil types in one oil change. That’s where problems begin.

5. The Oil Filter Doesn’t Need to Be Replaced Every Time

This might sound like a good shortcut, but it’s not. Your oil filter traps dirt, dust, and particles. If you change your oil but leave an old, dirty filter in place, the new oil will get dirty faster—and won’t protect your engine the way it should.

When you book a Nissan oil change appointment, the technician will replace your oil and filter together. It’s standard practice and smart engine care.

A fresh filter means:

• Cleaner oil
• Smoother performance
• Longer engine life

6. Thicker Oil Offers Better Protection

This myth is based on old-school thinking. Many drivers believe thicker oil gives engines a stronger shield. But modern engines aren’t built that way.

Every Nissan vehicle is engineered to work with a specific oil grade. Too thick, and it may not flow properly. Too thin, and it won’t protect moving parts.

For example, the Nissan Rogue might use a different oil grade than a Frontier, based on size, usage, and performance. Trust the recommendation in your owner’s manual or talk to a service expert. Thicker doesn’t mean better—it just means different.

7. You Can Top Off Oil Instead of Getting an Oil Change

If your oil level drops, it’s okay to top it off. But this shouldn’t be your only plan. Topping off doesn’t remove old, dirty oil. It just adds clean oil on top. Over time, this leads to a buildup and sludge that can clog your engine.

A full oil change replaces all of the old oil and gives your engine a fresh start. 

Skipping it can lead to:

• Poor performance
• Lower fuel economy
• Engine wear and tear

When in doubt, choose a full Nissan oil change and skip the shortcut.

Signs It’s Time for an Oil Change

When should you bring in your Rogue, Frontier, or Kicks for service? Here are signs it might be time:

Sign	What It Means
Oil change warning light	Your system senses low oil or dirty oil
Ticking or knocking sound	Oil is breaking down and not protecting parts
Dark, gritty oil	Oil is filled with debris
Reduced gas mileage	Engine isn't running as smoothly
Exhaust smoke	Could indicate oil burning inside engine

For peace of mind, make your next Nissan oil change appointment online or visit us in Montclair.

Engine Oil Tips Every Nissan Driver Should Know

We’ve covered a lot, but here are a few takeaways to keep in mind:

• Motor oil myths can lead to poor choices and costly repairs.
• Every vehicle—Kicks, Frontier, or Rogue—has different oil needs.
• Don't guess—ask a pro or follow your manual.

Want to learn more? Whether you're in San Bernardino, Montclair, or somewhere nearby, our team at Metro Nissan of Montclair is here to help.

Frequently Asked Questions About Engine Oil

Curious about how engine oil choices affect your Nissan? These common questions pop up all the time at Metro Nissan of Montclair—especially from drivers in Montclair and San Bernardino looking to take care of their Rogue, Frontier, or Kicks. 

Let’s break down the facts so you know exactly what matters (and what doesn’t).

Does it really matter what engine oil you use?

Yes, using the wrong engine oil can affect your engine’s performance, fuel efficiency, and longevity. Always use the oil type recommended in your owner’s manual.

Is it true you can't go back to regular oil after using synthetic oil?

No, you can switch between synthetic and conventional oil as long as you don’t mix them and use the correct oil grade for your vehicle.

Will synthetic oil hurt older engines?

No, synthetic oil won’t harm older engines if they are in good condition. In fact, it can offer better protection. However, very worn seals may show leaks more easily with synthetic oil.

What happens if you accidentally put regular oil instead of synthetic?

Your engine will still run, but performance and protection may be reduced, especially if your vehicle is designed for synthetic oil. Replace it with the correct oil at your next oil change.

These questions may seem small, but the right answers can help extend your vehicle’s life and save you from expensive repairs. If you’re ever unsure, our service team is here to help—book your Nissan oil change appointment today.

More to Explore for Nissan Owners

If you’re shopping for a new SUV, we recently compared some of the top contenders in the class. You can see how the Rogue stacks up against the Toyota RAV4 and Honda CR-V in this side-by-side SUV comparison blog.

For those interested in a midsize pickup, you’ll want to see how the 2025 Frontier performs on a budget. We broke it all down in this post about choosing the Frontier vs. Toyota Tacoma.

And if you're thinking about personalizing your pickup, check out this guide on Frontier trim levels, engine options, and colors.

Schedule Your Next Oil Change at Metro Nissan

Keeping up with oil changes is just one part of smart car care. Whether you drive daily through San Bernardino or cruise the streets of Montclair, the right service will keep your Nissan engine oil working its best.

Looking for something new? Explore our new inventory here and see what’s waiting for you.

Want to finance your next ride? Get started now with our easy finance application page. Need help? Contact us online or stop by our car dealership near you. We’re here to make your Nissan experience simple, smooth, and stress-free.