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How to Improve Your Winter Fuel Mileage with AMSOIL

Getting noticeably worse fuel mileage in the winter? Here are a few tips and tricks to improve it with our AMSOIL products!

Ever since we purchased a car with a fuel economy gauge, it has become my mission to constantly improve the reading. Even in rental cars I always see how can I keep that average MPG increasing! My wife will attest to this!

I may not be one of those who meticulously tracks fuel mileage but I do keep an eye on it in my personal mission. For example, our 2020 Jeep Grand Cherokee consistently averages 24-26 mpg on my commute to work and back home. That being said, I do notice a distinct drop in fuel mileage when the temps outside start to drop, making my personal challenge that much more difficult. In this post, we will look at some of the tips and tricks I have found to help get the best fuel mileage in winter!

The U.S. Department of Energy reports that a gasoline-powered vehicle’s fuel economy can drop 12% during short-trip driving at 20ºF (-6.6ºC) compared to 77ºF (25ºC).

Let's see why this happens and what we can do to help prevent it.

#1 - Cold Engines are Less Efficient

Whether you live in Texas or Minnesota, a cold engine is less efficient than a warm engine.

An engine has a "sweet spot" temperature that it operates at peak efficiency.

The main reason is air. Not fuel. Colder air is denser than warmer air.

Think of your engine as a massive air pump (which it technically is). Engines consume typically 14 times more air than the fuel it consumes. Denser air requires more fuel to mix with, which through all of the many sensors our modern cars have, the engine's computer increases the fuel mixture to compensate for the denser air to increase its performance, hereby decreasing fuel economy. This is great for all of us hot rodders, but for those who are trying to save money on their fuel expenses, it's bad news.

On the fuel side, colder fuel doesn't ignite as readily as warm fuel.

Have you noticed when you start your car on cold mornings it tends to idle higher and sound louder than normal? This is your engine's computer compensating for colder, denser air and adding more fuel, meaning there is more fuel being used in the combustion process. This allows the engine to start easily when it's colder.

That's why your modern, daily driver starts way easier than your old carbureted hot rod in the winter. As the engine warms, you will notice the idle decreasing which is the computer lowering the amount of fuel it needs, therefore improving your mpg's.

#2 - Idle Cars are the Devil's Ride

With the technology of remote start, getting out in the freezing cold to start and warm your car is nearly a thing of the past. With just the push of a button, you can get your car nice and toasty before you even pour your first cup of coffee.

Yes, it is amazing to hop in a warm car and not freeze your fingers on the gear shift or steering wheel, but the practice of warming your car reduces your fuel mileage quite more than you realize.

An idling engine can burn 1/4 to 1/2 a gallon of gas per hour!

Idling can also increase the chances of "fuel dilution". Fuel Dilution is where unburned fuel washes past your piston rings and contaminates your engine oil, the lifeblood of your engine.

Diluted oil loses its viscosity (thickness) which in turn causes increased wear on your engine along with forming a "varnish" and deposits that reduce your fuel mileage.

In brutal freezing temps, say -20ºF or colder, you may want to idle the engine longer before driving. Otherwise, a good minute of idling then easy driving for a few miles is a great practice to get into.

#3 - Snow Slows

While it may look effortless to see cars drifting around snowy, icy, corners; driving in the snow increases resistance on your wheels and tires, causing your engine to work harder and burn more fuel to travel down the highway.

Which is easier, walking on a nice level sidewalk? Or through four inches of snow?

#4 - Winter Fuels

Many fuel refineries switch to a "winter-blend" fuel in the fall, no this isn't the same as your pumpkin-spice latte. Winter-blend fuel is formulated to evaporate more easily at lower temperatures to aid in those cold starts I mentioned back in #1.

The downside is winter-blend gas contains less energy which in turn reduces your fuel-mileage.

"Summer-blend gas contains 1/7% more energy than winter-blend gas." - Enviromental Protection Agency (EPA)


Ways To Boost Winter Fuel Mileage

Most of us can’t avoid driving in snow. Or bitter cold. Or using winter-blend gas.

You can, however, check your tire pressure, which tends to decrease as the temperature drops. A tire that’s down 10 psi can reduce mpg by 1%.

You can also stop idling your vehicle for more than a minute or two before driving in the winter.

Also, remove unnecessary items that cut into your mpg, like a roof rack.

What else can you do?

The same thing you should do any time of year to maximize gas mileage.

#1 Use Synthetic Lubricants

Synthetic oils flow more readily when cold, which helps keep your engine protected while

reducing the wasted energy it would normally take to cycle the engine oil.

That's why I recommend using AMSOIL 100% Full Synthetic Oils on your next oil change.


Don't have time to change your own oil, schedule with us!


#2 Clean Fuel

Dirty fuel injectors also reduce fuel economy. Fuel must be atomized into a fine mist to burn efficiently during combustion.

The use of Fuel Additives will aid in not only keeping your fuel fresh but cleaning deposits in the fuel system,

Deposits on the injector tips disrupt the spray pattern and lead to streams of fuel instead of a fine mist, reducing mpg.

Keep injectors clean with a potent injector cleaner, like AMSOIL P.i. It reduces emissions and increases fuel economy up to 5.7%¹.

Once you have obtained that deep clean from AMSOIL P.i., like anything, you must maintain the cleanliness.

AMSOIL Upper Cylinder Lubricant will do just that and with an added bonus, it increases fuel lubricity which will help protect your cylinders and rings for maximum compression and power.

In fact, it delivers 18% more lubricity than Lucas² and 20% more than Sea Foam² for better retention of horsepower and fuel economy.

²Based on independent testing of AMSOIL Upper Cylinder Lubricant, Lucas Upper Cylinder Lubricant and Sea Foam Motor Treatment obtained on 02/13/2019 using the ASTM D6079 modified for use with gasoline.


Shop our full line of AMSOIL Fuel Additives for Diesel and Gasoline!


Keep these tips in mind to get the best fuel mileage this winter!

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