What Happens if I Put Wrong Fuel in My Car?

Misfuelling is quickly becoming one of the most discussed and feared causes of vehicle breakdown in the United Kingdom. In fact, at Fuel Doctor, it’s not uncommon for motorists to call us asking, I’ve put the wrong fuel in my car, what should I do?

Well, you shouldn’t panic if you happen to be a victim of misfuelling. Perhaps, you may take consolation in the fact that, as many as 400 motorists put the wrong fuel in their cars every day. However, this doesn’t imply that you shouldn’t get well acquainted with the entire situation and most importantly what to do. Here’s a rundown of the basics.

What Happens to Your Car?

For starters, petrol and diesel are different. Sure, they’re both petroleum-based, but the chemical structures vary. Likewise, how the engines convert energy from the fuel into mechanical energy is different. In other words, fuels behave differently depending on the engines that you put them into.

Petrol is a solvent. Therefore, when you put it in a diesel engine, it will strip away the oily coating that forms on the engine (remember, diesel is a lubricant). What this means is that with the protective layer gone, the seals will become dry and start to crack. By extension, your engine is likely to overheat and eventually fail.

On the other hand, if you put diesel into a petrol engine, you will create an oil coat inside. And, because diesel burns relatively slow, the spark plug will not be as effective. You are likely to end up with a smoking mess as the diesel attempts to find its way into the cylinder.

The long and short of it is that if you put diesel into a petrol engine, then you will have a problem starting your car. However, the damage is severe if you put petrol into a diesel engine. You may have to replace fuel pumps, filters, injectors, pipes, and the fuel tank. Besides, your technician may take twice as long to sort out the mess. Keep in mind that these problems will only occur if you run the engine after misfuelling.

What if You Turn on the Engine?

The first thing that you will do is to get the tank drained. Be sure to get in touch with a wrong fuel recovery service in the UK to do the job. Of course, you will have to fit in a new fuel filter. If you’d put diesel into a petrol engine, you may flush tank and restart your car.

Be on the lookout for some smoke as the diesel deposit burn off. You can consider using additives to help get rid of the residue quickly. The procedure is the same if you put petrol into a diesel engine.

Don’t forget that some automatic models require that you put the key into the ignition before you can move from Park to Neutral. Also, you can run your vehicle for a couple of minutes to a safer place. You’ll only need to tell the recovery service that you started your car.

Note – How soon you will get your vehicle on the road depends on your location at the time of misfuelling and how close you’re to the nearest wrong fuel recovery service.

Other than that, it can cost you anywhere between £3000 and £5000 in repair costs if you drove your car after misfuelling. Indeed, you will have to pay for the wrong and correct fuel.  The wrong fuel recovery service will charge you £150 to £200 to sort out the problem.

The Bottom Line

As stated, misfuelling is a common occurrence, and you shouldn’t be scared if it happens. Even then, you can take measure to prevent putting the wrong fuel in your car. You can, for instance, place items that will make it impossible for you to misfuel. There are products on the market that work by blocking a petrol pump if you insert it into a diesel vehicle.

You can also color the nozzle so you’ll always know the fuel inside. On top that, make sure that you read the pump label every time you’re refueling. Or, you can use little notes on the fuel cap door to serve as a reminder. Lastly, avoid distractions when re-fuelling.