What Happens If… You Put Diesel In A Petrol Car?

The fear of putting the wrong type of fuel in your car will definitely have coursed  through your body at one time or another if you’re a regular driver.

And, according to insurance company RAC, this is very common – and happens once every three minutes in the UK alone.

So here’s what you need to watch out for.

What happens if you put diesel in your petrol car?

• Misfiring engine

• Excessive smoke from your exhaust

• Engine cutting down

• Engine failing to restart

Although diesel is more expensive than petrol, putting it in your petrol car is actually significantly less serious than putting petrol in a diesel car. 

Basically, the diesel will coat spark plugs and the fuel system (which is why it misfires) and your engine will emit smoke, cut out or not start at all.

What happens if you put petrol in your diesel car?

• A loud knocking sound as you accelerate

• Excessive smoke from your exhaust

• Slower than usual acceleration

• Engine warning light lighting up

• Engine stopping completely

• Car struggling to restart

This is because petrol acts like a solvent instead of a lubrication oil to diesel cars. Turning on your ignition sends the fuel between the components and and increases friction, so part os the engine will be damaged.

That’s why you might have to replace your entire fuel system. 

What to do if you end up putting the wrong fuel in your car?

1. Leave your engine off – don’t even put your keys in the ignition

2. Tell the staff at the petrol station about your error

3. Put the car in neutral

4. Push it to a safe place

5. Call breakdown cover or RAC Fuel Patrol to drain and flush th system

6. Call your insurance provider ASAP

If you’ve already turned the engine on, turn it off as soon as you can, put it neutral and call breakdown cover and your insurance provider.

It will probably cost you quite a lot – especially if the entire fuel system needs to be replaced. 

What’s the difference between diesel and petrol?

The European Automobile Manufacturers’ Association has explained that the two fuels have very chemical make-ups, and completely different boiling points.

Diesel engines usually emit more CO2 and noxious gases according to the website carleasing.co.uk. 

But, these engines use less fuel overall as they’re more efficient and tend to last longer, and are usually slower to drive than petrol engines.

They’re also louder because of the way the fuel is burnt.

What about E10 fuel?

Some UK pump stations now stock E10 which is a more environmentally-friendly fuel, but it’s not compatible with every vehicle and could – over time – damage parts of your car, according to the RAC. But, it’s not as disastrous as mixing up petrol and diesel.

You can find out if your car is compatible with E10 by heading over to the gov.uk website here.