Gasoline, Diesel, and Ethanol FAQs | Esso and Mobil

Product and services FAQs

At Imperial, we meticulously engineer our products.

Why should I use Esso and Mobil branded fuel every time I fill up?
When you purchase gasoline at an Esso- and Mobil-branded gas station, you’re fueling with advanced Synergy gasoline. Engineered with 7 key ingredients to help improve fuel economy,** Synergy gasolines provide lower emissions and improved engine responsiveness** and are designed to provide corrosion protection and improved performance compared with gasolines meeting minimum government detergency standards. In addition, Synergy™ gasoline contains significantly higher detergent levels than CGSB requirements and has passed a series of deposit control performance tests.
**Improvements, such as fuel economy, are based on Synergy-branded gasoline, where and when available, compared to gasoline meeting minimum Canadian government detergency standards. Actual benefits will vary depending on factors such as vehicle type, driving style, and gasoline previously used. Concentration and availability of the 7 Key Ingredients may vary based upon factors beyond our control, including supply disruptions.
Does gasoline really need detergents?
Yes! Detergents are added to gasoline to help clean vital engine parts, including fuel injectors and intake valves. While the Canadian government has mandated that all gasoline marketed in Canada contains detergents, our gasoline contains significantly more than the minimum quantities required. A gasoline detergent is a lot like a household detergent, helping to remove any harmful deposit buildup on intake valves and keeping fuel injectors clean.*
What is unleaded gas vs. leaded gas?
If you filled your tank prior to the 1990's, you might remember that there were two choices of gasoline: "regular" and "unleaded." At the time, "regular" gasoline contained tetraethyl lead, which served as an octane booster in fuel. All vehicles manufactured after 1975 are built with catalytic converters and require unleaded gasoline. Catalytic converters help convert pollutants in exhaust to less toxic gasses such as carbon dioxide, nitrogen, and water vapor. Due to environmental concerns, leaded gasoline was phased out in the 1990’s and can no longer be sold at any gas station in Canada. Today, "regular gas" no longer refers to gasoline with lead content, but rather to a certain grade of unleaded gasoline.
How is gasoline performance determined?
The performance of gasoline is determined by multiple factors, including its antiknock quality (also known as octane rating), its volatility, and its detergency. Check your owner’s manual to see what octane rating is right for your vehicle.
What does antiknock mean?
Antiknock, also known as octane rating, is a measure of the gasoline's ability to resist knocking or pinging during combustion. Since it is gasoline vapor rather than liquid fuel that ignites, the air-to-fuel mixture must be correct for smooth combustion. The higher the octane rating, the greater the engine's resistance to knock. Some of the problems associated with knock are overheating of critical engine parts – namely valves, pistons and spark plugs. To minimize the effects of knocking, modern engines are equipped with knock sensors, which temporarily delay the spark timing in the piston’s compression cycle. While this prevents audible knocking, delaying the ignition spark also sacrifices engine efficiency.
What does detergency mean?
Detergency is the performance characteristic of a gasoline that refers to its ability to clean and protect the fuel delivery system, including the carburetor or fuel injectors, and intake valves. A gasoline detergent is fundamentally like a household detergent. It is a molecule that affixes itself to dirt particles. As gasoline passes through a car's engine, the molecule helps clean away dirt particles and helps to prevent any harmful deposit build-up.
What is Synergy Diesel Efficient™ fuel, and how does it differ from regular diesel?
Synergy Diesel Efficient diesel fuel was developed in the same laboratories as our racing fuels. It has been engineered to help improve fuel economy help boost engine performance, reduce maintenance and provide cleaner emissions.
Is Synergy Diesel Efficient™ fuel only for commercial vehicles?
To find Synergy Diesel Efficient fuel for your personal vehicle, use our Esso™ and Mobil™ site locator to find a station near you. To find Synergy Diesel Efficient fuel for your trucking fleet, use our cardlock™ site locator to find your nearest Esso Commercial Cardlock™.
How will Synergy Diesel Efficient fuel benefit my vehicle?
Tested in independent laboratories and in multiple real-world applications, Synergy Diesel Efficient fuel showed a 2 percent quantifiable fuel economy benefit.* It has been found to help improve engine performance, help clean fuel injectors, help remove deposits and enhance corrosion protection.

*Based on internal and third-party vehicle engine testing, laboratory testing, and/or industry or other scientific literature. Basis for comparison for all claims is versus diesel without detergent additive. Vehicle type, engine type, driving behaviour and other factors also impact fuel and vehicle performance, emissions and fuel economy. Synergy Diesel Efficient may be used in other heavy-duty and light-duty vehicles but results will vary.

Where can I purchase Synergy Diesel Efficient fuel?
Synergy Diesel Efficient fuel is offered at many markets in the United States and Canada. The next time you fill up your diesel car or truck, make sure to try diesel fuel that helps improve mileage and deliver more power. Just stop into your local Esso or Mobil station and look for the next-generation Synergy Diesel Efficient-branded pumps. Synergy Diesel Efficient fuel for fleets is also available in select markets at our expanded network of Esso Commercial Cardlocks™.
Where can I go to learn more about Synergy Diesel Efficient diesel fuel?
Visit our Synergy Diesel Efficient for commercial fleets page or our Synergy Diesel Efficient for passenger vehicles page to learn more.
Will gasoline with ethanol affect my vehicle’s fuel efficiency?
Ethanol contains less energy than gasoline per gallon of fuel, but any changes in the fuel economy performance of your vehicle are expected to be minimal.
If I have water in my vehicle’s fuel system can I use ethanol-blended fuel?
Water in your vehicle’s fuel system may cause problems regardless of whether ethanol is present or not. A number of products are available to remove water from your fuel system. You should consult your mechanic for a recommendation.
Will my vehicle require additional maintenance?
Regular vehicle maintenance is always recommended, regardless of fuel type. Gasoline containing up to 10% ethanol is suitable for use in most vehicles and will not require additional maintenance.
Are there reasons, other than using a gasoline with an octane level lower than recommended in my vehicle owner’s manual that may cause knocking to occur?
A small percentage of vehicles may require higher octane gasoline under certain operating conditions because of variations in engines of the same model due to manufacturing tolerances, or because of an unusual build-up of engine deposits. A small percentage of vehicles may knock because of variations in engines of the same model due to manufacturing tolerances, or because of an unusual build-up of engine deposits. Other factors such as extremely hot weather, changes in altitude or hard driving conditions (like towing a heavy load) may also cause knocking. Many modern vehicles are equipped with an electronic device that detects and eliminates light knocking before you hear it.
Is there a situation where the octane my vehicle needs would differ from the level recommended in my owner’s manual?
In general, the octane a vehicle needs aligns with the manufacturer’s recommendation. However, each vehicle is different, owing to factors such as manufacturing variability, mileage, type of operation and general condition. As a result, some vehicles may require a higher octane, particularly after an initial period of operation. If knocking or pinging begins to occur, using a higher octane grade may resolve the problem.
Is a touchless car wash as good as a brush wash?
If you wash your car regularly, touchless can be better because nothing touches your car.  This will help to reduce damage that may occur from a brush wash.
Will a touchless car wash remove all dirt?
touchless wash will get most cars clean and dry but may have difficulty removing some grime, road film, tar, or bird droppings

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