What Happens When You Pump The Wrong Fuel For Your Subaru Car?

It’s a mistake many drivers make — pumping the wrong type of fuel into your car. Whether you’ve accidentally used diesel in a gasoline engine or put premium fuel into a vehicle designed for regular unleaded, it’s more common than you might think. If you’ve just realized you’ve made this mistake, don't worry! Here’s what can happen when you put the wrong fuel in your Subaru and what steps you should take to resolve it. For expert help, you can always rely on Empire Subaru.

1. Immediate Engine Trouble

One of the first signs that something’s off is your engine. If you've accidentally filled your Subaru with diesel instead of gasoline, your engine may sputter, stutter, or even stall altogether. Diesel is thicker and doesn’t burn the same way gasoline does, which means it can cause immediate issues for your engine. If you’ve mixed up premium with regular fuel, the effects may not be as dramatic, but you could still notice a rough start, unusual noises, or poor performance.

If you notice any of these issues right after fueling, it’s a good idea to stop driving and get help immediately. Continuing to run the engine with the wrong fuel will only make the problem worse.

2. Damage to Your Fuel System

Your Subaru’s fuel system is designed to work with specific types of fuel. When you pump the wrong fuel, it can cause damage to the system. Diesel in a gasoline engine can clog fuel injectors, fuel lines, and the fuel pump, leading to expensive repairs. On the other hand, using the wrong octane level of gasoline can cause poor combustion, which can gradually wear down the engine over time.

Even if you’ve used the wrong fuel for a short distance, it's a good idea to get your fuel system checked. Contaminants like diesel or even the wrong grade of gasoline can cause long-term issues with the injectors or fuel pump.

3. Contaminated Fuel Tank and Lines

If you’ve accidentally put the wrong fuel in your Subaru, the fuel tank and lines could be contaminated. The incorrect fuel can mix with the gasoline and cause a sludge-like substance, clogging your fuel filter and damaging the system. In some cases, the wrong fuel may continue to circulate through the system, causing further damage as it goes.

If this is the case, it’s essential to get the fuel tank flushed by a professional mechanic. The quicker you get the fuel drained and the system cleaned, the better.

4. Engine Components Can Be Damaged

In a worst-case scenario, using the wrong fuel can lead to damage to the internal engine components. For instance, diesel fuel in a gasoline engine doesn’t burn as efficiently, and unburned fuel can accumulate in the engine, potentially damaging pistons, cylinders, and valves. If you’ve been driving with the wrong fuel for an extended period, this can result in costly repairs.

Even if you’ve just put regular gasoline in a car designed for premium fuel, you may hear knocking sounds or experience reduced power, which could also result in long-term engine damage if ignored.

5. Repair Costs Can Add Up Quickly

If you don’t act quickly, the cost of repairs can skyrocket. The longer you drive with the wrong fuel in your Subaru, the more likely it is that you’ll cause damage to your engine, fuel system, and other critical components. The good news is, if you catch the mistake early, draining the tank and cleaning the fuel system can help minimize any serious damage. But if the wrong fuel has been circulating for a while, you might have to replace parts of the fuel system, like the fuel pump or injectors.

6. What to Do If You’ve Put the Wrong Fuel in Your Subaru

First and foremost, stop driving. Don’t try to start the engine again, as this will only spread the wrong fuel throughout the system. Your best bet is to call a roadside assistance service or a mechanic who can help drain the fuel safely and get your Subaru back to normal. Some shops, like Empire Subaru, can provide this service and help you avoid further complications.

Once the tank is drained and the system cleaned, the mechanic will likely replace the fuel filter and check the entire system for any issues. If you’ve only driven a short distance with the wrong fuel, you might be able to get away with minimal repairs, but if you’ve driven far, the damage may be more extensive.

7. How to Prevent Fuel Mix-Ups in the Future

Now that you know the dangers of putting the wrong fuel in your Subaru, how can you avoid making this mistake again? First, always double-check the pump before you start fueling. Most stations clearly label their fuel options, and your Subaru’s manual will tell you exactly what type of fuel to use. Some newer models also have labels on the fuel cap or dashboard to remind you of the correct fuel type.

Another helpful tip is to take your time when refueling, especially if you’re driving in unfamiliar areas. Slow down, check the labels, and ensure you're putting in the correct fuel. It might seem like a small thing, but it can save you from a big headache down the road.

If you’ve realized that you’ve put the wrong fuel in your Subaru, don’t panic. Act fast, get your Subaru to a mechanic for a fuel drain, and you’ll be on your way to getting your car back in tip-top shape. For expert help with this issue and more, visit Empire Subaru to schedule an appointment today.