Does insurance cover putting the wrong fuel in the car?

Misfuelling often happens when we’re a bit distracted. You might grab the wrong pump, or maybe you forget which car you’re driving and end up putting diesel in a car that takes gasoline. Unfortunately, by the time you realize it, it’s already too late. While it’s a common slip-up, the impact can be serious—ranging from engine damage to repair costs that could reach thousands of dollars. So, does car insurance cover this kind of mistake? Well, that depends on the details of your policy.

Is misfueling covered by car insurance?

Putting the wrong fuel in your car is surprisingly a common, accidental mistake that could happen to anyone. But don't assume it's automatically covered by your car insurance. Although many policies cover accidental damage, some have a specific clause that excludes coverage for misfuelling, draining and cleaning. This means your insurer might not pay for any damage caused by filling up with the wrong fuel.

It's always important that you check the terms and conditions of your car insurance policy to understand what’s covered for misfuelling. Coverage varies widely between providers—some don’t cover misfuelling at all, while others might cover repair costs or the expenses for draining and cleaning the tank, and some might even cover both. Your best bet is to contact your insurance company or broker to find out if misfuelling is part of your coverage or specifically excluded.

When might insurance cover putting the wrong fuel in your car?

As we mentioned, whether your car insurance covers misfuelling truly depends on what your policy says and what type of coverage you have. Here are the types of coverages that might cover misfueling your vehicle:

Comprehensive coverage

Misfuelling could fall under comprehensive coverage. Comprehensive car insurance is an optional coverage that protects your car by covering losses or damages that aren’t usually included in collision-related incidents. If your car suffers damage due to accidentally putting the wrong fuel in your car, you could potentially file a comprehensive insurance claim.

So, if misfuelling causes immediate, serious damage—like you start the car, and the engine destroys itself—then, as long as your policy covers misfuelling, you may be able to file an insurance claim. However, remember, the keyword here is damage. This means your comprehensive insurance won't cover the cost of towing and draining the fuel from your vehicle.

Say you start driving and notice problems shortly after. For instance, if you put diesel in a gasoline car, it’ll stop running pretty quickly. You call for a tow, and it turns out there’s no real damage—just a tank full of the wrong fuel, so your engine stopped working. In this case, you’re facing a maintenance issue, not an insurance claim. Although draining the diesel can be pricey, it likely isn’t covered by insurance since the car isn't technically broken; it just needs cleaning.

Mechanical breakdown insurance

Another possibility is if you carry optional mechanical breakdown insurance. Mechanical breakdown insurance (MBI) helps cover repair costs if certain parts of your car break down because of a mechanical failure—not because of an accident or regular wear and tear. It’s designed to cover issues like engine breakdowns that aren’t caused by an accident.

So, if you have this coverage and your engine fails due to a mechanical issue, like using the wrong fuel, your policy may cover the repair costs to fix or replace your engine after you pay any deductible. However, MBI also comes with exclusions, so you'd have to ask your car insurance provider or broker whether misfuelling is included in your MBI policy or not.

Roadside assistance

While optional roadside assistance won't cover the costs of draining your fuel or repairing damage, it can cover the cost of having your car towed to a mechanic. So, if you realize immediately that you used the wrong fuel at the fuel pump and call a tow truck, or if your car breaks down on the side of the road soon after driving away, your roadside assistance can help cover the cost.

What does misfuelling mean?

Your car needs a specific type of fuel, which you’ll find listed in the owner’s manual and often inside the fuel door. Here are some common fuel types you’ll find at most gas stations:

• Unleaded
• Super unleaded
• Premium unleaded
• E85 ethanol
• Diesel

Misfuelling is what happens when you use any fuel to fill your fuel tank other than what’s recommended, which can lead to serious issues for your vehicle.

What happens if you put the wrong fuel in your car

The impact of using the wrong gas or fuel depends on what and how much you’ve put in. Even a small amount of the wrong fuel can cause the engine to run inefficiently, produce unusual noises, or, in some cases, stall altogether. Below, we will explore what happens if you accidentally use different types of incorrect fuels in your car:

Premium gas

If you accidentally put premium gas in a car that doesn’t need it, there’s no harm done. But if you put regular gas in a car that requires premium, you may hear a rattling sound from the engine. The engine’s computers will adjust to avoid damage, but you might notice a dip in fuel efficiency and performance.

Gas engine with diesel fuel

If you accidentally fill a gas car with diesel fuel, you’ll likely face some costs and hassle. Since gas engines can’t combust diesel, your car likely won’t start. If it does start, it'll likely start smoking. The diesel fuel can quickly clog up the fuel filter and injectors. Diesel is thicker than gasoline, which means it can quickly make a mess of your car’s internal systems. While it’s not usually a major car engine issue, you’ll still need to get the tank drained, which can cost several hundred dollars, plus possible towing fees.

Diesel engine with gasoline

On the other hand, putting gas in a diesel car is the most expensive misfuelling mistake. In this situation, the vehicle may still run for a bit. But if you don’t catch it in time, it can lead to serious engine damage, costing much more to fix.

Diesel fuel naturally lubricates the fuel pump as it flows through, so when gasoline is used instead, it’s similar to running an engine without oil. This lack of lubrication creates a lot of friction, causing metal particles to break off and move through the fuel system. If these particles reach the injectors, they can cause major issues. Since the injectors have tiny openings that could easily get clogged, the entire system could be damaged, leading to expensive repairs. Also, since gasoline is thinner and ignites faster than diesel, it generates excessive heat that can damage the diesel engine’s fuel sensors.

E85 ethanol

Many newer flex-fuel vehicles are built to run on E85 ethanol fuel, which is mostly made from biomass materials like corn. If you accidentally fill up a regular gas car with E85, your check engine light will likely come on. While that’s never reassuring, a one-time mix-up shouldn’t harm the engine. Just to be safe, check with a mechanic to ensure no issues develop.

However, if you use E85 regularly in a non-flex-fuel car, the high ethanol content can cause serious corrosion in the fuel system over time. Plus, using E85 in a vehicle not designed for it might void your engine warranty.

Symptoms to watch for if you put the wrong fuel in your car

If you're worried you might have used the wrong fuel, there are a few key warning signs to watch out for:

• The car struggles to start when you turn the ignition
• Strange engine noises when idling
• Loss of power at normal speeds or on the highway
• Excess smoke coming from the exhaust
• The engine doesn’t shut off when you turn off the ignition

If you notice any of these symptoms, it’s a good idea to pull over and call for roadside assistance. These signs could point to a serious issue that could worsen and lead to major engine damage.

Steps to take if you misfuel your car

Not all misfuelling mistakes are the same. If you just put the wrong octane fuel in a regular gas engine, there’s no need for drastic measures—just make sure you fill up with the correct fuel next time. But if you accidentally put gas in a diesel car, it probably won’t start, and you’ll need to have the tank flushed. Here’s what to do if you realize you’ve used the wrong fuel:

Don’t start the car

Ideally, you’ll catch the mistake before turning on the ignition. Starting the engine can lead to serious damage. If you’ve already started it, turn it off as soon as possible.

Move your car to a safe spot

If you’re parked at the gas station pump, put your car in neutral and push your car to a nearby safe area to keep it out of the way. If you're driving, pull over to the side of the road safely.

Call for assistance

Now it's time to call for help. If you don’t have roadside assistance as part of your car insurance coverage, contact a tow truck company to tow you to your car mechanic, who can thoroughly flush your fuel lines and gas tank.

Check with your insurance

Contact your insurer to see if misfuelling-related costs—like repairs, tank draining, and cleaning—are covered under your car insurance policy.

How to avoid choosing the wrong fuel

It’s easy to accidentally use the wrong fuel, especially with a new or rental car. To help avoid this mistake:

Know your car

Diesel cars should only use diesel. For gas cars, check your owner’s manual for the minimum octane rating—make sure the fuel you choose meets or exceeds that number. Typically, regular gas has an octane level of 87, premium is 91 or 93, and plus is somewhere in between. Cars that need premium often list the octane level on the gas cap, while others may just recommend it.

Pay attention at the pump

Stay focused while fueling (leave your phone in the car, for example). Carefully check the buttons and nozzles to ensure you’re selecting the right fuel, especially at a new gas station where the layout may be different than you used to. You can also consider adding a sticker to the gas cap to help you remember what type of fuel to use.

Use a misfuelling prevention device

In Canada, diesel nozzles are designed so they cannot fit into a gas tank. However, that's not the same for gasoline nozzles in diesel tanks. To avoid this, you can buy a diesel tank insert that blocks gas nozzles or look for cars that come with this feature as standard—some manufacturers now include it in all diesel models.

Is buying a fuel-efficient car worth it?

Many drivers choose fuel-efficient cars for a few good reasons. For one, using less fuel means fewer emissions, which makes these cars better for the environment. Plus, fuel-efficient cars can save you money since you won’t need to stop at the pump as often—a big plus with today’s high gas prices. So, if you’re deciding between two models, it’s worth checking their fuel efficiency, especially if you’re on the road a lot.

What is a good fuel economy in Canada?

In Canada, we measure fuel efficiency using litres per 100 kilometres (L/100km). To understand what qualifies as good gas mileage here, you’ll want to check the average fuel consumption for different types of vehicles and think about where you do most of your driving—whether it’s mostly in the city, on the highway, or a mix of both.

Contact BrokerLink for comprehensive car insurance

Car insurance may cover putting the wrong fuel in your car, but it all depends on the type of coverage you have and what your policy excludes. If you have any questions about whether your insurance covers misfuelling, reach out to BrokerLink. You can speak with one of our licenced insurance brokers to get all the details on auto insurance and how it protects you as a driver. Here are a few types of car insurance coverage that a BrokerLink advisor can help you explore:

• Liability car insurance
• Accident forgiveness coverage
• Comprehensive car coverage
• Uninsured automobile insurance
• Accident benefits coverage
• Collision car insurance

A BrokerLink insurance advisor won’t just answer your questions—they’ll take the time to understand your needs and find coverage that fits your budget. You can reach us by phone, email, or in person at any one of our locations throughout Canada. We also encourage you to take advantage of our free online quote tool that can provide you with a competitive quote in minutes.

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