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Types Of Gas A Lexus RX350 Takes (Explained)

Types Of Gas A Lexus RX350 Takes (Explained)

On this blog, we do a lot of research regarding specific questions about different cars. Today we’ll look at the Lexus RX350 and answer what kind of gas this car requires. We’ve gone through the owners’ manuals of the 2007 – present-day RX350 to find the answer. Here’s a quick answer:

Lexus RX350 manufactured in or before 2011 take premium unleaded gasoline with an octane rating of 91. Lexus RX350 manufactured from 2012 onwards take regular unleaded gasoline with an octane rating of 87.

However, that doesn’t tell the whole story. Below we’ll dive into what kind of gas this car takes. We’ll talk about reformulated gasoline, E-85, and gasoline with additives. Should or shouldn’t you use this for the RX350? We’ll also talk about the fuel mileage of each generation as well as possible knocking noises and so much more. Read on!

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Infographic explaining the different fuel types for a Lexus RX350

Details About The Octane Rating Of The RX350

One of the first things we need to clarify immediately is the use of premium and regular gasoline in different generations of the RX350. As stated, up to 2011, the earlier generation made use of premium gasoline with an octane of 91, whereas the newer generations all make use of regular gasoline with an octane of 87.

However, in the car world, we often see that engines that have 91 recommended can also occasionally use 87 octane whenever 91 octane is not available. However, let it be clear that this is not the case for the earlier generations of the RX350. Under no circumstances should you fill up pre-2012 models of the RX350 with 87 – 89 octane gasoline.

If 91 octane, for whatever reason, is not available, then it’s highly advised you make use of 93 – 95 octane since this won’t hurt the engine. Some people even believe that higher octane gasoline is always a better choice. This is not true because a 91 octane engine cannot derive benefits from higher octane fuels. However, higher octane fuels at least won’t hurt the engine or cause problems with your Lexus RX350.

The same is true for the newer generations that use 87 octane. If this kind of fuel is not available, please opt for 89 octane or higher. Using lower octane gasoline is always a worse choice and can affect how many miles your RX350 lasts.

What Types Of Gasoline Can And Can’t Be Used?

Besides knowing the proper octane levels, there are several other things that you should be aware of concerning the gasoline you use in your RX350. These mainly include different kinds of additives used in the fuel.

Reformulated Gasoline

First, there’s the use of reformulated gasoline compared to non-reformulated gasoline. Reformulated gasoline is gasoline that’s become popular over the past decade because it burns cleaner than its counterpart. For this reason, it has even become mandatory in some areas of the United States.

Therefore, it’s good to know that Lexus recommends reformulated gasoline. Its use won’t negatively affect the engine or decrease its performance. Overall, it’s just a better type of gasoline that should be used whenever available.

Gasoline/Oxygenated Blends Or E-85

Another essential part of the gas we need to talk about is the use of oxygenated blends such as ethanol, methanol, or MMT. These chemicals can be added to gasoline to make them burn cleaner. As Lexus states in their owner’s manuals, the use of these kinds of gasoline is advised because it’s better for the environment.

However, there’s a limit to the percentages you can use in each generation of the RX350. For example, RX350s made in or before 2015 can take gasoline with a maximum of 10% ethanol. However, RX350s made from 2016 onwards can handle gasoline with a maximum percentage of 15% ethanol.

This means that, depending on the generation, the RX350 is compatible with E10 or both E10 and E15. On the other hand, it also means that other popular ethanol blends such as E30 (30% ethanol) and E85 (51 – 83% ethanol) cannot and shouldn’t be used. The same is true for mixtures that contain methanol or MMT; these cannot be used at all.

Using ethanol in a percentage that exceeds the limits, or using methanol or MMT in any amount, will damage the engine and the fuel system, and this kind of damage is not covered under any warranty.

Gasoline With Added Materials

Finally, we have to talk about additives in these types of gasoline. As a general rule of thumb, just using any additive marketed to you is a bad idea. This is because many aftermarket additives contain elements that are harmful to the fuel system and engine.

These elements are most likely going to be some form of silicon or micro metals. Even though many additives are supposed to clean your engine, many will harm your engine. Also, octane boosters are advised against since it’s better to immediately tank the proper octane levels.

To prevent you from figuring out what kind of additives are good or bad, it’s best to buy gasoline from certified TOP TIER gasoline retailers. Lexus, like many other carmakers, actually endorses buying this gasoline. This is because it already has all the proper additives mixed into it, and it has been proven to clean the engine and improve the lifespan of the engine. Visit to find a retailer near you.

What If I Hear A Knocking Noise From The Engine After Refilling?

Hearing a knocking noise in a car is a normal occurrence. However, it’s essential to listen carefully to the loudness of the knocking noise. A slight knocking noise is normal, especially when the car achieves peak performance (such as when towing or driving up a hill).

However, a loud knocking noise is a problem, especially if you refilled the car. In this case, you’re likely using gasoline with a lower than recommended octane level, and the car is not handling this well.

In this instance, the best thing to do is stop the car and call your dealer or garage. It’s very likely the car needs to be drained from its fuel, and the fuel filter will need to be changed. Ignoring the knocking noise will result in severe mechanical damage.

Does the Lexus RX350 Have Good Gas Mileage?

In the United States, the three generations of the RX350 have all been sold with the same 3.5 engine configuration. Below, we’ve outlined the fuel economy of each generation.

We found that, in general, the gasoline versions of the RX350 aren’t that fuel-efficient. Furthermore, it’s interesting to note that the 3.5 engine hasn’t become that much more fuel-efficient over 15 years. Also, the RX350 doesn’t have a hybrid version (you’ll have to pick the RX450h to get a hybrid) which means the fuel economy is quite bad overall.

2007 – 2012


2012 – 2015


2016 – Present-day


What’s The Gas Tank Size Of A Lexus RX350?

All generations of the Lexus RX350 have a gas tank size of 19.2 gallons or 75 liters. Assuming an average price of $4 per gallon, this means it costs $76,80 to fill up a Lexus RX350.

Closing Thoughts

In wrapping up our exploration of the Lexus RX350’s fuel requirements, we’ve discovered that, like many vehicles, its specifications and needs have evolved over time. From the use of premium unleaded gasoline in the models up to 2011, to the shift towards regular unleaded gasoline from 2012 onwards, understanding these changes ensures the longevity and optimal performance of your vehicle. The fuel you choose does more than just power your car; it impacts efficiency, engine health, and the overall driving experience. By being well-informed, you can make the best decisions for your Lexus RX350. Whether you’re curious about reformulated gasoline, the implications of E-85, or simply seeking ways to enhance fuel mileage, always refer back to your vehicle’s owner manual and prioritize quality fuel to keep your RX350 running smoothly.


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