Does the Lexus RX350 Require Premium Gas?

The type of fuel you use does more than power your Lexus RX350. It also affects engine performance. You want to get the most out of your luxury vehicle, so what type of gas should you use?

Does the Lexus RX350 require premium gas? The answer is no. You don’t have to pay the extra money for premium-grade fuel, but it may improve engine performance. Look for fuel with an octane rating of 89 or higher.

Want to know more about why you want to use premium gas in your Lexus RX350? Keep reading. I’ll cover this and more in the following paragraphs.

Should You Use Premium Gas in a Lexus RX350?

Premium gas is more expensive, but it can also protect your engine from wear and tear. The top-grade gas can help remove build-ups from the engine, improving its performance and fuel efficiency.

The fuel has a higher octane rating, usually around 92 or 93. The rating refers to the fuel’s compression rating before ignition. Higher octane fuel is better equipped to prevent engine knocking. It’s the rattling noise you occasionally hear when you first start the vehicle. The knocking comes from the gas igniting too soon.

Most high-performance vehicles, like the RX350 from Lexus, have engines with higher compression rates. To prevent engine knocks, I suggest to use a higher octane fuel. It ignites slower, preventing any excess wear on the engine.

What Happens if You Use a Lower Octane Fuel in a Lexus RX350?

Constantly fueling up with premium gas is expensive. The differences in gas prices at the pump are based on octane ratings. The higher this rating the more you pay.

An octane rating of 92 or 93 gives your engine plenty of protection and can boost fuel efficiency for highway miles. You can drive further before having to fill up the tank.

Even though mechanics prefer premium fuel, you can save some money by dropping a grade.

Using fuel with a lower octane rating will not damage the vehicle’s engine. The Lexus RX350 runs on a mid-grade fuel. Look for gas with an octane ratio of at least 87.

It has the compression ratio necessary to prevent engine knocking. You can also save a few dollars every time you fill the tank up.

You may notice a slight loss in fuel efficiency, but that is not enough to have a serious impact on your wallet.

The RX350 averages around 27 miles per gallon (mpg) on the highway with premium fuel. Using mid-grade gas, the mpg only drops to 26. It’s also the same with city driving. You only lose a mile or so in fuel efficiency.

Can You Use Low-Grade Fuel in a Lexus RX350?

When you see the prices at the pump it’s tempting to go for the gas with the lowest price. The octane rating affects how much you pay for every gallon of fuel.

Your Lexus RX350 will give you a great performance with 87 octane fuel. It’s a step below premium grade and perfectly fine to use in your vehicle.

Using fuel with an octane rating below 87 can cause engine damage.

Your RX350 comes with an engine sensor that helps protect the motor from knocking. Fuel with a lower octane level can trigger the sensor, preventing the fuel from temporarily igniting. The delay helps ensure the knocking doesn’t damage any engine parts, but it also has downsides.

The delay in fuel ignition reduces engine power, decreasing the car’s performance capabilities. If the sensor is broken, engine knocking is common, and it can cause expensive repairs.

Does the Lexus RX350 Require Premium Gas

What Causes Engine Knocks?

Fuels with not enough octane for the motor can cause engine knocks. It occurs when gas that’s not ignited mixes with air in the combustion chamber. The engine pistons compress the fuel and air, and the spark plug starts the ignition process.

Gas doesn’t always ignite evenly. It can take the flame some time to heat the mixture throughout the combustion chamber. As the pistons are compressing the fuel, it can spontaneously ignite in the unburned area of the chamber. When the mixture is heated, engine knocks occur.

Higher octane fuels do not self-ignite. The gas heats up at a higher degree, preventing engine knocks.

How Do You Know It Needs Premium Fuel?

You don’t need to research the various types of gas to know what type of fuel is at the pump. Most gas stations take care of it for you by labeling the pumps.

Gas pumps usually have three buttons with different numbers. The numbers represent the octane ratio. The middle button is typically for mid-grade fuel, with the other two denoting low and premium gas.

The octane rating for premium fuel can vary by state. You may fill up with a 93 octane fuel in one state and a 92 rating in another. The octane ratio varies by one or two percent in premium gas, but it is always higher than 89.

Can You Use Diesel Fuel in a Lexus RX350?

Diesel fuel is being phased out. Eco-friendly laws and regulations are making these types of vehicles obsolete.

You can still find a few gas stations selling diesel, but you don’t want to put it in your Lexus RX350. You can not use diesel in a vehicle that takes unleaded gasoline.

They are different fuel types and not all will not power a Lexus engine. It can cause the engine to lock up. Often the only solution is to replace the engine, and it’s not cheap.

You can save your engine if you accidentally fill up with diesel, but it will take some work.

Do not start the vehicle. You do not want the fuel running through your engine. Instead, you need to drain the fuel tank.

Remove the bolt and place a bucket underneath to catch the fuel. It is a good idea to stop by a mechanic after you drained the fuel to have the engine flushed.

Frequently Asked Questions 

What gas should I use in my Lexus RX350?

As you are getting ready to fuel up again, you have a few options. You want to use unleaded gas with an octane ratio of at least 89. You don’t need to use premium gas, but don’t go down to the lowest tier.

What happens if you put regular gas in a premium car?

Your Lexus RX350 doesn’t need premium gas, but it can improve the vehicle’s performance. If one of your vehicles requires premium fuel, do not use anything else. Fuel with a lower octane ratio can cause engine damage from pinging or knocking.

What problems do Lexus RX350 have? 

Using premium or mid-grade fuel helps prevent many problems. But the RX350 is still known for having a few common issues. Oil and water pump leaks are frequent issues. RX350 owners also complain about rack and pinion leaks.


The Lexus RX350 does not need premium fuel, but it doesn’t hurt. The higher octane ratio can improve engine performance and fuel efficiency. They also priced it higher than other grade fuels.

You can use a mid-grade fuel with no problems and save a few dollars on gas costs. Just make sure the octane ratio is at least 89 to avoid engine wear and tear.

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