Writing about Cadillacs is almost a daily practice on this blog. Today we will look at what type of gas is best suited for the Cadillac ATS. The ATS was made between 2013 – 2019 and had quite some different engines equipped during its lifespan. Therefore, there are also additional gasoline requirements for many of them. Here’s a quick answer:
Cadillac ATS with a non-turbocharged 2.5L or 3.6L V6 engine take regular unleaded gasoline with an octane rating of 87. ATS with a turbocharged 2.0L or 3.6L V6 engine take premium gasoline with an octane rating of 91 if they were made before 2016 and 93 octane if they were made between 2017 – 2019.
However, this doesn’t tell us the whole story. In the article below, we’ll discuss what kind of gasoline is used for what type of 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 ATS generations. Read on!
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Fuel Requirements Per Generation
We have already given you a summary of what kind of gasoline is best used in the Cadillac ATS. However, in its six-year manufacturing run, the ATS was equipped with five different types of engines. Furthermore, these engines all had additional gasoline requirements that changed throughout the years.
Between 2013 – 2015 the ATS had a 2.5L LCV and a 3.6L naturally aspired LFX engine, with 87 octane gasoline recommended.
Between 2013 – 2019 you could also opt for a 2.0L turbocharged LTG. The 2013 – 2016 model year has 91 octane recommended, but from 2017 onwards, this changed to 93 octane as a recommendation. Furthermore, these engines could also take 87 octane if premium gasoline was temporarily unavailable. An interesting note here is that Cadillac states 99 octane or higher should be used for this engine when it’s used for track racing.
Between 2016 – 2019 there was a 3.6L naturally aspired LGX, which has 87 octane gasoline recommended. There was also a 3.6L turbocharged LF4 which has 93 octane recommended but could also take 91 octane if 93 wasn’t available.
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 the 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 even become mandatory in many states to use this kind of fuel.
Therefore, it’s good to know that all engines used in all generations of the Cadillac ATS are designed to take both reformulated and non-reformulated gasoline. Consequently, you don’t have to worry about what kind of gasoline you put in your engine (at least not for this criteria).
However, we have to say that Cadillac recommends using reformulated gasoline whenever possible. Like other carmakers, GM (owners of Cadillac) realize that using this type of gasoline 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
We also have to talk about the use of oxygenated blends of gasoline. These kinds of gasoline contain ethanol or methanol, which are biosources of gasoline. Because they’re typically made from corn, their emissions are cleaner, and therefore their use is encouraged in the United States.
Ethanol is the most important oxygenate to talk about. Typically, all engine types of the Cadillac ATS are designed to take ethanol with a maximum percentage of 15% ethanol. This means that E10 (10%) and E15 (15%) can be used in all ATS vehicles.
On the other hand, there’s also gasoline with 30% ethanol (E30) or 51 – 85% (E85). The last one is also referred to as FlexFuel. This means the gasoline you use is 85% ethanol and 15% gasoline. Some Cadillac ATS are compatible with FlexFuel but certainly not all of them.
Cadillac ATS that can take gasoline with a maximum percentage of 85% ethanol have a yellow fuel cap which indicates they’re safe to use E85 (this was the case for some ’13-’15 3.6L V6s). Furthermore, Cadillac encourages using E85 if your vehicle is equipped to drive on this type of fuel.
However, do be aware that the use of E85 is discouraged when temperatures fall below 0 Fahrenheit (-18 Celcius). This is because ethanol blends are more difficult to ignite for engines, and this becomes even harder when temperatures drop.
Gasoline With Added Materials
Typically, car manufacturers recommend against the use of fuel additives. Fuel additives are usually 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 the use of 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 this gasoline 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.
Suppose you’re not capable of buying TOP TIER gasoline because this type of gasoline is not sold in your area. In that case, Cadillac recommends that you fill up your tank with ‘Fuel System Treatment PLUS’, which is an additive only sold by Cadillac and GM dealers. This should happen at every oil change or roughly 9,000 miles.
What If I Hear A Knocking Noise From The Engine After Refilling?
If you hear a knocking sound coming from the engine, but it’s not very audible, then this is an entirely normal occurrence, especially in situations that require peak performance (such as when towing or driving uphill); an engine may make a knocking sound. However, there’s more to it.
If the knocking sound becomes very loud or happens right after refueling, you most likely have larger problems. In the case of the Cadillac ATS, you’re probably using gasoline that has a lower than recommended octane rating, or you’re using E85 in a FlexFuel vehicle. Still, the engine has trouble igniting the gas because of lower outside temperatures.
If you’ve used gasoline with a lower than recommended octane rating, the engine is likely misfiring. As we saw earlier, some types of engines can take 87 or 91 octane when higher octane numbers are preferred. However, in some cases, the engine still can’t take this type of gasoline that well.
It’s best you stop the car immediately and call the dealer. The vehicle will need to be drained from its fuel, and the fuel filter will need to be replaced to prevent the engine from completely failing.
If the problem occurs because you’re using E85 gasoline, it’s best to add premium gasoline with an octane rating as high as possible to the engine. This will balance out the ethanol levels in the E85 gasoline and provides easier ignition. If this is not possible, follow the steps mentioned above (call the dealer, drain it).
Also read: 8 Common Cadillac ATS Problems
What’s the Fuel Economy Of A Cadillac ATS?
To fully understand the relationship of the Cadillac ATS with its gasoline, we have to understand what kind of fuel economy the different engines have. For this, we’ve comprised data in the table below. As you would expect from a Cadillac, the numbers aren’t all that great.
As you can see, the 2.5L engine (available in the 2015 ATS) performs best, but with a combined MPG of 25, it’s still nothing to write home about. Furthermore, it’s interesting to note that the FlexFuel option performs terribly. However, this is normal for FlexFuel: on average, E85 has 30% less energy, but it’s also 30% cheaper to buy, which means everything levels out.
| Engine | Combined | City | Highway |
| 2.0L | 23 | 20 | 29 |
| 2.5L | 25 | 21 | 32 |
| 3.6L (2013-2015) | 21 | 18 | 26 |
| 3.6L FlexFuel (2013 – 2015) | 16 | 13 | 19 |
| 3.6L (2016+) | 23 | 19 | 29 |
| 3.6L Turbo (2016+) | 20 | 17 | 25 |
What’s The Gas Tank Size Of the Cadillac ATS?
Cadillac ATS made from 2013 onwards all have a fuel tank capacity of 16.5 gallons or 62.5 liters.
Sources
- https://my.gm.ca/cadillac/en/content/dam/gmownercenter/gmna/GMCC/dynamic/2013/cadillac/ats/en/2013_Cadillac_ATS_2nd_Print_Manual_en_CA.pdf
- https://my.gm.ca/cadillac/en/content/dam/gmownercenter/gmna/GMCC/dynamic/2015/cadillac/ats/en/2015_Cadillac_ATS_Manual_en_CA.pdf
- https://my.gm.com/content/dam/gmownercenter/gmna/dynamic/manuals/2016/Cadillac/Multi-Model%20PDFs/2k16%20ATS+V%20Owner%20Manual.pdf
- https://cdn.dealereprocess.org/cdn/servicemanuals/cadillac/2019-ats.pdf
- https://www.fueleconomy.gov/feg/search.shtml?words=cadillac+ats
Hi! My name is Stefan; I’m the owner and lead writer at TheDriverAdviser.com.
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