You left the house late this morning, so you’re in a rush to get to work. The fuel tank is low, though, so you stop at a Costco gas station (because they typically have the best diesel prices) en route, grab the nozzle, and start pumping while eying your watch. It isn’t until you pay closer attention that you notice something – you’ve put gas in your diesel engine.
Panic sets in as you realize what’s happened. Putting gasoline in a diesel engine isn’t a simple mix-up—on the contrary, it can lead to severe mechanical issues and engine damage. So what can you do?
This article outlines the potential consequences of this mistake and what you can do to save time and money while preventing further damage to your vehicle.
The Key Differences Between Gasoline and Diesel
Gasoline, which is lighter and more volatile, ignites with the help of a spark from a plug. Diesel, on the other hand, relies on the heat generated from compressed air to ignite on its own. This difference affects engine operation: diesel engines are engineered for the compression and ignition of diesel fuel, which contains more energy and burns slower than gasoline. Putting gasoline in these engines can cause combustion issues and related damage.
Think of diesel as a marathon runner – steady, with a slow burn that maximizes energy over time. Gasoline, in contrast, is like a sprinter, designed for quick bursts of power. Putting one in the other’s shoes leads to nothing but trouble.
Short answer: diesel is an oil, gas is a solvent.
Immediate Consequences of Gasoline in a Diesel Engine
Even just a bit of gas – as little as 1-2% – can mess up a diesel engine.
If gasoline is put into a diesel engine, the engine’s behaviour will change immediately or shortly after. While the severity of the damage depends on how long the engine runs with the wrong fuel, but here are some of the first signs to look for:
- Loss of Lubrication: Diesel fuel lubricates the engine’s components, particularly the fuel pump and injectors. Gasoline lacks these lubricating qualities, leading to increased wear on these parts. This can cause the fuel pump to fail prematurely.
- Premature Ignition: Gasoline ignites at a much lower temperature than diesel. The result is premature combustion, known as knocking, which can damage the pistons, cylinder walls, and injectors of the diesel engine.
- Fuel System Damage: Diesel engines rely on the thickness and energy density of diesel fuel. Gasoline is much thinner and will not provide the same fuel efficiency. This inconsistency can strain the fuel pump and other components of the system.
- Severe Engine Damage: If the gasoline isn’t removed, it will continue circulating, worsening the damage. The longer the engine runs on the wrong fuel, the greater the risk of catastrophic failure, potentially requiring the replacement of major components or the entire engine.
If you accidentally fill up your trusty diesel truck with gasoline on a cold winter morning, you might notice rough idling and strange sounds within minutes. By the time you get home, the engine could struggle to perform, leaving you with a bigger problem.
What to Do If You’ve Put Gas in a Diesel Engine
If you’ve made this mistake, fortunately, there are steps you can take to minimize the damage. They include:
- Don’t Start the Engine: If you realize your mistake before turning the key, do not start the vehicle. This prevents the gasoline from circulating throughout the engine. If the engine hasn’t been started, a simple draining of the tank will likely resolve the issue. Diesel engines are tough machines.
- Turn Off the Engine Immediately: If you’ve already started the vehicle and it’s running, turn it off as soon as possible. The quicker you stop the engine, the better your chances of limiting the damage.
- Drain the Fuel System: Tow the vehicle to a mechanic to drain and clean the fuel tank, fuel lines, and injectors. The fuel system components then need to be carefully inspected for any damage.
- Check for Damage: Once the gas is cleared out, a mechanic will check for potential damage, especially to the fuel injectors, fuel pump, and pistons. If gasoline has circulated for a long time, these parts may need to be replaced.
There are also some great responses and feedback on this Reddit thread.
Long-Term Risks of Misfuelling
Using gasoline can cause long-term issues, even after the fuel has been removed. Some of these risks include:
- Fuel System Contamination: Gasoline can corrode sensitive parts of the diesel fuel system, leading to failures down the line. Injectors in particular, are at risk of corrosion, which could cause uneven fuel distribution or blockages in the future.
- Engine Wear and Tear: Since gasoline lacks lubrication, key components like the pistons and fuel pump will likely wear out sooner. Over time, this can cause the engine to lose efficiency and power.
- Lower Resale Value: Vehicles that have experienced misfueling often see a drop in resale value. Prospective buyers might be wary of purchasing a car undergoing major repairs or misfueling-related damage.
How to Avoid Misfuelling
Preventing this problem is easier than fixing it, so always verify which pump you’re using. Diesel pumps often have larger nozzles, which can help prevent accidental misfueling. Other recommendations include:
- Label Your Fuel Cap: Some diesel vehicles come with labelled fuel caps, but if yours doesn’t, you can add a simple sticker to remind yourself (or other drivers who might use your car) to fill up with the right fuel.
- Use Preventative Devices: Aftermarket devices can be installed in your fuel tank to prevent the wrong fuel nozzle from fitting. These devices are handy for fleet vehicles or households that use both gasoline and diesel vehicles.
Questions About Diesel Engine Maintenance and Repair?
Accidentally putting gasoline in a diesel engine is frustrating, but if you act quickly, you can prevent severe damage. The important thing is to avoid running the engine and get the fuel system drained as soon as possible. Stay alert when fueling up, and your car will perform reliably.We can’t help with a fuel mix-up, but we can make dang sure that your car looks its best.. We offer a wide range of premium-quality mobile vehicle detailing in Thorold and the Greater Niagara area, so let us handle the dirty work while you enjoy a clean, well-maintained vehicle. Book your appointment today and give your car the care it deserves.
