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The Types Of Gas A Chrysler 300 Uses (Explained)

The Types Of Gas A Chrysler 300 Uses (Explained)

The mileage of a vehicle is important as a perimeter of performance, and it depends on the gasoline that the vehicle runs on. We will talk about the Chrysler 300 with a focus on what kind of gas it takes.

An overview of the owner manuals of Chrysler 300 models manufactured since 2005 briefly tells us that:

Chrysler recommends 87 octane gasoline for 2.7L engines, 89 octane for 3.5L and 5.7L engines, and 91 octane for 6.4L (SRT8) engines of 1st generation Chrysler 300. In 2nd generation, 87, 89, and 91 octane are recommended for 3.6L, 5.7L, and 6.4L (SRT8). In 3rd generation 6.4L (SRT8) models, 95 RON or higher is recommended.

The answer to the question of what gas a full-sized car such as the Chrysler 300 takes is not yet complete, and we will further discuss the type of fuels that Chrysler recommends for engines of three generations of Chrysler 300.

We will explore other gasoline options in the market that could be used in these engines and their effect. We will also try to understand the gasoline options that are well suited to the engines that have powered Chrysler 300 since 2005.

Let’s get started!

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Fuel Requirements Based On Engine Type


The third-generation Chrysler 300 was launched in 2015. Since then, it has been offered in three engine configurations, i.e., 3.6L, 5.7L, and 6.4L SRT. All the engines are mated to an 8-speed automatic transmission. The 3.6L engine runs on 87 octane gasoline which provides satisfactory performance and emission control.

The 5.7L engines run on regular unleaded gasoline having an 87 octane number, but 89 octane high-quality plus gasoline, which allows the engine to operate at optimum levels. The 6.4L SRT engine operates on high-quality unleaded gasoline of 95 RON or above. Chrysler recommends that 98 RON should be used in this engine to get optimum performance from it.

Using gasoline with a higher octane number than the recommended octane rating of Chrysler does not provide any additional advantage over the regular unleaded gasoline in these engines. Higher octane number also does not improve the engine performance. Therefore, Chrysler has advised against using premium gasoline in engines, i.e., 3.6L and 5.7L, as they perform well on regular gasoline and “plus” gasoline.

Chrysler 300 from manufactured 2015 to the present are designed to run on up to 15% ethanol blended in regular gasoline. Ethanol percentage greater than that and E-85 fuel is only recommended in Flex Fuel Vehicle. Using such fuels in non-FFV engines may cause performance issues and damage the engine components. The FFV variant of the Chrysler 300 was not offered in the 3rd-generation.


The second-generation Chrysler 300 models were launched in 2011, and they were produced till 2015. This generation was offered in three engines. The 3.6L engine runs on high-quality unleaded regular gas with an octane rating of 87.

The same recommendation goes for the type of gas used in the Chrysler 200, or even the Chrysler Pacifica, among others. The manufacturer does not recommend using premium gasoline in this engine because it does not offer any performance enhancement compared to regular unleaded gasoline.

The 5.7L engine is designed to run on high-quality regular unleaded gasoline of octane, rating 87 to 89. The manufacturer suggests using gasoline of 89 octane for the 5.7L engine to perform at an optimum level. The use of premium gasoline is discouraged in 5.7L engines because of the lack of any added performance advantage over regular gasoline.

The SRT variant of this generation comes equipped with a 6.4L engine. This engine, when run on gasoline of octane rating 91 or higher, delivers optimum performance and mileage while adhering to the emission regulations.


Chrysler 300 was launched in 2005, and its first generation was manufactured till 2010. Four engines are offered in the first-generation, i.e., 2.7L, 3.5L, 5.7L, and 6.1L. The 2.7L engine is designed to perform well and provide effective emission control on high-quality unleaded regular gasoline of octane number 87. Running on premium gasoline does not provide a substantial benefit as compared to regular gasoline in this engine.

The 3.5L and 5.7L engines are designed to perform well and follow emission standards when run on gasoline with octane numbers 87 to 89. Chrysler, however, recommends the use of high-quality gasoline of octane number 89 to get optimum performance figures out of this engine. Similar to the 2.7L engine, Chrysler does not recommend premium gasoline for these engines because of no added benefit over regular gasoline.

The first-generation Chrysler 300 SRT is equipped with a 6.1L engine. This engine performs well and adheres to the emissions control standard when run on high-quality unleaded gasoline of octane number 91 or more.

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

A variety of gasoline products are available in the market. Some of these products are recommended by Chrysler for the 300 models, and some are not recommended. We will now discuss these gasoline products in detail.

Reformulated Gasoline

Reformulated gasoline is made by blending oxygenates with regular gasoline. Oxygenates blended with gasoline can bring down the emission levels in engine exhausts. This type of gasoline brings improvement in air quality.

Many states have made it compulsory to use reformulated gasoline as a part of the initiative to protect the environment by cutting emissions. Chrysler recommends using reformulated gasoline in all the engines that have been offered across its three generations ranging from 2.7L to 6.4L.

Gasoline/Oxygenated Blends Or E-85

Gas companies often blend substances – oxygenates – in gasoline. A very common oxygenate that is blended in gas is ethanol. In some states which see harsh winters, oxygenates are specifically blended in to cut down exhaust emissions.

The most common ethanol blend in gasoline is E-85 fuel. This fuel is made by blending 85% ethanol and 15% gasoline. Vehicles that use E-85 are called Flex Fuel vehicles. The label can identify these vehicles on their gas filler caps specifying “E-85 (Ethanol) or unleaded gasoline only.”

First-generation Chrysler 300 engines are not designed to run on ethanol-blended gasoline. The second and third-generation engines are designed to run on unleaded regular gasoline or up to 15% ethanol blended with gasoline. So far, only the 3.6L engine of the second-generation Chrysler 300 (FFV variant) is designed to run on regular unleaded gasoline or E-85.

E-85 compatible vehicles (FFVs) can run on E-85 or unleaded gasoline or even mix these two. Chrysler advises the owners of 300 FFV (2nd-gen 3.6L engine) to avoid changing the fuelling pattern between regular unleaded gasoline and E-85. If the need arises to change the fuel type, then the following protocol should be adopted to avoid the vehicle from getting driveability issues such as a hard start:

  • Refill the tank with a minimum of 5 gallons of the fuel type that you want to switch to.
  • Right after refueling, drive the car around for a minimum of 5 miles.

While using E-85 in FFV, Chrysler recommends looking out for the following issues:

  • Using E-85 fuel in a region with a harsh environment can cause performance and driveability issues of the vehicle. Therefore, always use E-85 fuel adjusted to the season especially if the temperature drops below 0°C.
  • Additives are added to gasoline to enhance its properties. Some additives in gasoline when blended with E-85 are not compatible. This leads to the accumulation of deposits in the engine. In case a deposit is built up in the engine, Chrysler suggests using MOPAR® Injector Cleaner fluid or Techron. Click here to find Techron on Amazon.

Gasoline With Added Materials

Chrysler 300 engines are designed to run on high-quality unleaded fuels. Apart from high-quality gas, some beneficial additives such as detergents and agents prevent corrosion and provide stability. Chrysler recommends using gasoline with these materials added to it. These beneficial additives help the vehicle perform better, deliver more mileage per gallon, and monitor the emissions.

Gasoline marked as Chrysler recommends top Tier Detergent Gas to minimize deposits in the fuel system components or the engine. Top Tier Detergent Gas contains a greater quantity of detergent than normally added to provide effective protection against deposit build-up.

Chrysler recommends fuel cleaning systems for cleaning Chrysler 300 fuel systems, but it is also advised against their misuse. The nature of many fuel system cleaners is very aggressive, and their excessive use can potentially damage the rubber diaphragm and gasket in the engine.

Gasoline With MMT

MMT stands for Methylcyclopentadienyl Manganese Tricarbonyl. This metallic additive is usually blended in the gasoline to increase the octane number. Studies show that gasoline without any additive vs. the gasoline blended with MMT does not differ in terms of performance.

On the other hand, a major disadvantage of using MMT blended gasoline is compromising the life of spark plugs. It also hampers the emission control system to work properly.

Chrysler recommends avoiding using MMT blended gasoline in Chrysler 300. Gasoline retailers are not bound by law to label MMT blended fuel. Therefore, it is important to ask the fuel retailer regarding MMT blend in the gasoline and avoid gasoline with blended MMT.


The three generations of Chrysler 300 were offered with engines designed to run on gasoline. These engines cannot run on biodiesel. It can be one of the reasons not to include biodiesel as a potential fuel for Chrysler 300 in its owner’s manual.

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

In the user manuals published across three generations of Chrysler 300, the manufacturer has mentioned light knocking sound with the gasoline recommended for the vehicle’s operation. This kind of subtle engine knocking is normal, and it is not an indication of an engine malfunction.

If you’re not sure what engine knocking is then consider checking this video:

While light knocking can be ignored, heavier knocking is a sign of trouble. Because of the high risk of potential engine damage, the vehicle should be taken to a dealer for an inspection as soon as possible.

Other than the SRT variant, Chrysler engines should not be run at octane numbers lower than 87, and for the SRT version, using gasoline with octane numbers less than 91 can cause engine failure.

Chrysler also recommends changing the brand of gasoline and getting better-quality gasoline. Bad quality gasoline can cause engine malfunction.

Does the Chrysler 300 Have Good Gas Mileage?


2016 to present Chrysler 300 equipped with a 3.6L engine has a combined MPG of 19-23. The 5.7L engine has a combined MPG of 16-19. The 6.4L engine has the lowest combined MPG of 11-18.

EngineLowest Combined MPGHighest Combined MPG
3.6L, 8-spd, automatic1923
5.7L, 8-spd, automatic1619
6.4L, 8-spd, automatic1118


The 2011-2015 Chrysler 300, equipped with a 3.6L engine and 5.7L engine, has a combined MPG of 19-23. The 5.7L engine running on E-85 and the 6.4L engine on premium gasoline has the lowest combined MPG of 14-17.

EngineLowest Combined MPGHighest Combined MPG
3.6L, 8-spd, automatic1923
5.7L, 8-spd, automatic1923
5.7L, 8-spd, automatic, E-851417
6.4L, 5-spd, automatic1417


The 2005-2010 Chrysler 300 equipped with a 2.7L engine has the highest combined MPG of 18-21. The 3.7L engine has the next highest combined MPG of 17-19. The 5.7L engine has the lowest combined MPG of 16-18.

EngineLowest Combined MPGHighest Combined MPG
2.7L, 4-spd, automatic1821
3.5L, 5-spd, automatic1719
5.7L, 5-spd, automatic1618

What’s The Gas Tank Size Of A Chrysler 300?

The 2005-2010 Chrysler 300 has a fluid capacity of 18-19 Gallons (68-72 liters) depending on the engine size. The 2011-2015 Chrysler 300 has 18.5 Gallons (70 liters) fuel capacity across all variants. Similarly, 2016-present Chrysler 300 models have a fuel capacity of 18.5 Gallons (70 liters) across all engine variants.

How Much Does It Cost To Fill Up A Chrysler 300?

It will approximately cost $57.45 – $72.50 to fill up different engine variants of the 2005-2010 Chrysler 300. For the 2011-2015 Chrysler 300 models, it will cost $59.05-$70.59 approximately to fill up all gasoline variants and approximately $50.727 for the E-85 FFV variant.

For 2016 to present Chrysler 300, it will cost approximately $59.05-$70.59. At $52.15 approximately, it will be the cheapest to fill up 2016 to present models of Chrysler 300, and it will be costliest to fill up at $81.40 in California.

A great tip for further optimising milage per gallon would be to research the rolling resistance of different types of tires and their bolt patterns.

Closing Thoughts

The type of gasoline you use in your Chrysler 300 is a critical factor that directly impacts the vehicle’s performance and longevity. Based on extensive engineering assessments, Chrysler specifies recommended octane levels for each engine variant.

Adhering to these recommendations is essential, since deviating from the specified octane levels can result in pre-ignition, decreased performance, and potential engine damage.

For a deep dive into the dangers of mixing fuel types, don’t miss our article on “Why Mixing Different Octane Gasoline May Destroy Your Car“. Additionally, for information regarding the differences and similarities between E85 Flex Fuel and premium gasoline with an octane of 91 – 93 our article provides valuable insights.

In summary, the gasoline you choose for your Chrysler 300 is not merely a routine decision—it is a vital component of vehicle maintenance. Happy driving!


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