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The Types Of Gas A Cadillac SRX Uses (Explained)

The Types Of Gas A Cadillac SRX Uses (Explained)

The SRX was first introduced in 2003 as a 2004 model and discontinued in 2016. All were gasoline models, with none produced as diesel engine variants.

Today we will try to tackle some other SRX-related information, such as fuel requirements based on engine type, types of gasoline, what to do in case of engine knock, etc.

But let’s first answer the main question: What types of gas does a Cadillac SRX uses?

2004-2009 models had two engine types; a 3.6 L V6 designed for 87 octane unleaded gasoline and a 4.6 L V8 designed for 91 octane level gas. 2010-2016 models had three engine options; 2.8 L V6 with 93 octane level premium gas recommended, 3.0 L V6, and 3.6 L V6, designed for unleaded 87 octane.

Of course, that’s not all and we will take a detailed look at the available gasoline types to understand the benefits of using the right fuel type for an engine or, conversely, the consequences of using the wrong fuel type, what octane rating means, and the latest improvements in gas blends. Finally, we will look at some fuel-related facts and stats for the Cadillac SRX.

So, let’s get started!

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Does The Cadillac SRX Require Premium Gasoline?

Second Generation (2010-2016)

The 4.6L of the first generation was discontinued, and 2.8L / V6 and 3.0L / V6 were introduced instead. Cadillac recommended regular 87-octane, unleaded fuel for the 3.0 L and 3.6 L, a cleaner blend E85 can also be used in the 3.6 L option. The smaller 2.8 L engine was turbo-charged and required premium gas with an octane rating of 93.

87 octane, 89 octane and 91 octane fuel levels explained

First Generation (2004-2009)

Manufactured between 2004-2009, the first-generation SRX had options for two engine types; a 3.6L / V6 and a 4.6L/V8 configuration.

The 3.6L / V6 engine was designed to use regular unleaded gasoline with an octane rating of 87. The larger 4.6 L engine with AWD required more power; hence the recommended fuel type was a 91 octane rating for optimal performance.

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

To meet stringent emission regulations, petroleum refineries produce cleaner and more efficient fuel blends that give better mileage and clean the engine, thus resulting in lower carbon emissions. Additionally, there is a drive to introduce more eco-friendly biofuels.

Reformulated Gasoline

To control sulfur content in gasoline, EPA developed regulations in 1999 that sought to reduce sulfur content to 80 mm max in gas through the Reformulated Gasoline (RFG) program. RFG is, therefore, a cleaner and more efficient gasoline blend. RFG is mandatory in cities with high smog levels and is optional elsewhere.

RFG has been shown to reduce smog levels and toxic pollutants in the environment. Along with other measures, it is contributing to bringing down smog levels in the U.S. Cadillac encourages the use of reformulated gasoline whenever it’s available.

Gasoline / Oxygenated Blends

First of all, it’s good to know that the Cadillac SRX can take a maximum of 10% ethanol for all engine types. However, this is only the case if the vehicle isn’t specifically a FlexFuel vehicle. More on that below.

Ethanol levels for cars explained, E10, E15 and E85

E85 or FlexFuel

One of the most popular oxygenated blends is E85 or FlexFuel. It is formulated with 85% ethanol and 15% gasoline. It has its advantages and disadvantages, which are given below:


  • It is eco-friendly because ethanol burns cleaner than gasoline.
  • The biggest advantage is that FlexFuel vehicles are designed to burn whatever proportion of the mixture is in their combustion chamber.


  • Since ethanol, used in blended gas, comes from corn and sugar, any crop used for extracting ethanol loses its agricultural use.
  • Ethanol can cause corrosion and damage to the engine.
  • Ethanol is also not as economical as gasoline, with lower miles per gallon compared to conventional gas.
  • When the ambient temperature is above 90° F (32° C), the car experiences hard starting and rough idle following startup, even if the above recommendations are followed.

To find out whether your vehicle is designed to run on FlexFuel, take a look at your car’s gas cap or the fuel gauge on the car’s dashboard. If the vehicle has a yellow gas cap or there are E-85 marking on the SRX, it’s safe to use FlexFuel or any percentage of ethanol below that.

Gasoline With Added Materials

Typically, car manufacturers recommend against the use of fuel additives. Fuel additives are sold as octane-boosting substances or advertised to help keep your engine clean.

Boosting octane is a reasonably useless practice since it’s recommended and safer for your engine to buy premium gasoline at a certified retailer. Furthermore, cleaning additives are also advised against because they typically contain silicones or metallic, damaging the engine instead of cleaning it.

Therefore, Cadillac instead recommends using TOP TIER gasoline sold by certified retailers. This type of gasoline already has all the proper additives mixed into it, and it has been scientifically proven that it helps keep your engine clean and perform optimally. It also doesn’t cost any more than non-TOP TIER gasoline. You can find a retailer on

If you do not have access to TOP TIER gasoline in your area and have a Cadillac SRX manufactured after 2008, Cadillac recommends using a GM-made fuel additive.

In earlier model years, this was referred to as ‘GM Fuel System Treatment PLUS’, whereas later, the product was named ‘GM Fuel System Treatment Cleaner’ or ‘ACDelco Fuel System Treatment Plus’. Add this additive to your fuel every 15,000 miles if TOP TIER gasoline is not used.

Gasoline With MMT

MMT or Methylcyclopentadienyl manganese tricarbonyl is used as an octane enhancer in gasoline produced by Afon Chemicals. MMT is allowed in U.S. gasoline at a level equivalent to 1/32 grams per gallon manganese.

Studies conducted on vehicles in which MMT was added to the gasoline showed that it resulted in several issues such as plugging monolithic converters, increased hydrocarbon emissions, and caused excessive spark plug deposits.

MMT seems to have more downsides than any substantial advantage and hence not recommended by car manufacturers, including Cadillac. The following is taken from the SRX owner manual.

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

Hearing a slight knocking sound coming from the engine is an entirely normal occurrence. Especially when the car is performing at peak levels, such as when towing, a slight knocking sound can be heard. However, if this knocking sound becomes very audible and happens right after refilling, you may have more significant problems.

First off, in this case, it’s very likely you’re using gasoline with a lower-than-recommended octane rating. For example, Cadillac states 87 octane can be used in some instances even though 91 or 93 octane is recommended. However, if this creates a situation where you hear a loud knocking from the engine, it’s advised to stop immediately.

This knocking noise tells you the engine is misfiring because it can’t handle the octane level used. It’s best to stop your car immediately and call your dealer or garage. Your car will need to be drained from its fuel, and the fuel filter will need to be replaced. Continuing to drive will result in severe engine damage.

Does the Cadillac SRX Have Good Gas Mileage?

This section shows the fuel economy data for the various SRX versions. We will give figures for the 2WD version. The values for AWD are about 1 MPG lower. The combined MPG is 55% of City MPG and 45% of highway MPG. Note: All MPG figures are for the 2WD option, which has a slightly better economy rating.

Second Generation (2010-2016)

dark blue 2016 cadillac srx parked in front of dealership
EngineMPG CityMPG HighwayCombined MPG
2.8 L / V6152218
3.0 L / V6182521
3.6 L / V6172419

First Generation (2004-2009)

black 2007 cadillac srx parked in parking lot
EngineMPG CityMPG HighwayCombined MPG
3.6 L / V6152318
4.6 L / V8132016

What’s The Gas Tank Size Of A Cadillac SRX?

The first-generation Cadillac SRX has a fuel capacity of 20 gallons, equivalent to about 76 liters, while the second generation has a fuel capacity of 21 gallons or about 79 liters.

Closing Thoughts

The type of gas your Cadillac SRX requires hinges largely on its engine type, and adhering to these specifications is not something to take lightly. Using the wrong fuel type can lead to a myriad of issues, from engine knocking to reduced performance and potential engine damage.

It’s paramount to understand what octane rating means and its implications for your SRX’s performance. While newer gas blends offer some interesting options, sticking to your SRX’s recommended octane level is the safest bet for maintaining that Cadillac performance and luxury.

For a deeper dive into your SRX’s capabilities, check out the Drive System A Cadillac SRX Has, and to explore its hauling prowess, don’t miss our post on the Cadillac SRX Towing Capacity.

Remember, fuel is the lifeblood of your SRX, so give it the good stuff and it will return the favor with reliable, spirited performance. Happy driving!


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