Types Of Gas A Cadillac CTS Takes (Explained)

Writing about Cadillacs is almost a daily practice on this blog. Today we will look at what type of gas best suits the Cadillac CTS. The CTS ended up having three generations, all of which have additional gasoline requirements. Here’s a quick answer:

All generations and engine types of the Cadillac CTS can take premium, unleaded gasoline with an octane rating of 91. However, the early 2.6L and 2.8L V6 have 87 octane recommended, whereas other V6s (especially the ones with a turbo) or the V8 engines have 93 octane recommended.

However, this doesn’t tell us the whole story. In the article below, we’ll discuss what kind of gasoline is used for what engine. Furthermore, we’ll discuss different additives that can and can’t be used, what percentage of ethanol is acceptable, and the gas tank size of the different CTS generations. Read on!

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Infographic explaining the different fuel types for a Cadillac CTS.

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Does The Cadillac CTS Require Premium Gasoline?

First, it’s essential to discuss the different types of gasoline required. We gave you a summary above; however, there’s much more nuance to the guidelines than that answer would make you believe. Below, we’ve split up the generation and the available engine types.

2014 – 2019

For the third generation of the CTS, Cadillac switched some of the fuel recommendations halfway through the generation.

For the 2015 – 2016 2.0L L4 turbo engine, Cadillac recommends using premium gasoline with 91 octane, although the 2017 – 2019 version of this engine has 93 octane recommended. In both cases, 87 octane can be used temporarily when premium gasoline is unavailable.

For the 3.6L V6 LFX or LGX engine, Cadillac recommends regular gasoline with an octane rating of 87.

87 octane, 89 octane and 91 octane fuel levels explained

For the 2015 – 2016 versions of the 3.6L V6 twin-turbo LF3, Cadillac recommends using 91 octane, although the 2017 – 2019 versions of this engine have 93 octane recommended. In the case of the 2017 – 2019 engines, these can also take 91 octane temporarily, but 87 octane can never be used in this engine.

The 6.2L V8 LT4 engine has 93 octane recommended, although it can take 91 octane temporarily when 93 octane is unavailable.

2008 – 2014

Cadillac simplified the gas requirements substantially for the second generation of the CTS. Models made between 2008 – 2014 with a V6 engine take regular gasoline with an octane rating of 87.

The 6.2L V8 takes premium gasoline with an octane rating of 91, but Cadillac also recommends using 93 octane when optimum performance is required. Furthermore, 87 octane can be used temporarily for this engine if premium gasoline is unavailable.

2003 – 2007

The first generation of the CTS has some interesting fuel requirements. In the owner’s manuals of this generation, Cadillac states different fuel requirements for different types of engines.

The 2.6L and 2.8L V6 engines take regular gasoline with an octane rating of 87. On the other hand, the 3.6L V6 engine requires a minimum of 87 octane. However, Cadillac recommends using 89 – 93 octane for situations where optimum performance is required (such as when towing a trailer).

For the 3.2L V6, 5.7L V8, or 6.0L V8, Cadillac recommends using 91 octane by default; however, these engines can take 87 octane temporarily when 91 octane is unavailable. The use of 87 octane in these engines will reduce acceleration and performance.

If you’re interested in the different gasoline requirements for all Cadillacs, please read the article we just linked.

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

Reformulated Gasoline

First, we need to discuss the use of reformulated and non-reformulated gasoline. Reformulated gasoline is gasoline that is designed to burn cleaner than non-reformulated gasoline. For this reason, it has become widely popular in many regions of the United States. It has become mandatory in many states to use this fuel.

Therefore, it’s good to know that all engines used in all generations of the Cadillac CTS are designed to take both reformulated and non-reformulated gasoline. Consequently, you don’t have to worry about what gasoline you put in your engine (at least not for this criterion).

However, we have to say that Cadillac recommends using reformulated gasoline whenever possible. Like other carmakers, GM (Cadillac owners) realizes that this gasoline type is better for the environment. Furthermore, this type of gasoline doesn’t diminish the performance of your engine in any way, shape, or form, and it also carries the same price as non-reformulated gasoline.

Gasoline/Oxygenated Blends Or E-85

Secondly, there’s the use of oxygenated blends of gasoline. These types of gasoline are widely popular in the United States, but there are some guidelines you need to be aware of.

First, oxygenated blends of gasoline typically contain a specific concentration of ethanol or methanol. Ethanol or methanol are made from bio-sources (such as corn), and they burn cleaner than gasoline without ethanol or methanol. This is why they’re used in the United States.

For the first generation of the Cadillac CTS (2003 – 2007), only gasoline with a maximum percentage of 10% ethanol (also referred to as E-10) is accepted. Gasoline with a higher percentage of ethanol will severely damage the engine in this generation.

Ethanol levels for cars explained, E10, E15 and E85

All generations of the Cadillac CTS manufactured from 2008 onwards can take gasoline with a maximum percentage of 15% ethanol (referred to as E-15).

This means that gasoline sold as E-30 or E-85 (FlexFuel) can and should not be used in the CTS. Doing so will damage the fuel system and won’t be covered under any warranty.

Furthermore, it’s necessary to know that using methanol in any concentration is prohibited in all generations of the CTS. Using methanol will also damage the fuel system significantly.

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 toptiergas.com.

Intake valve deposits with conventional vs. TOP TIER fuel

Engine deposits with conventional vs. TOP TIER fuel — Intake valve deposits with conventional vs. TOP TIER fuel

If you do not have access to TOP TIER gasoline in your area and have a Cadillac CTS 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.

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.

What’s The Gas Tank Size Of the Cadillac CTS?

Cadillac CTS manufactured between 2003 – 2007 have a fuel tank capacity of 17.5 gallons or 66.2 liters.
Cadillac CTS manufactured between 2008 – 2014 have a fuel tank capacity of 18 gallons or 68.1 liters.
Cadillac CTS manufactured between 2015 – 2019 have 19 gallons or 72 liters of fuel tank capacity.

Sources

Stefan K.

Hi! My name is Stefan; I’m the owner and lead writer at TheDriverAdviser.com.

I’m an active writer on this blog myself, as well as a novice car mechanic. For the really technical stuff, I find writers with experience as a mechanic or who have studied mechanical engineering.

Read more about our fantastic team on our about page!

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