Misfuelled? How Much Wrong Fuel is Too Much Wrong Fuel in Your Car?

Put the wrong fuel in your car? If you have mis-fuelled with petrol in a diesel car or diesel in a petrol car, you may well now be apprehensive about what longer term damage you may have done and the attached cost. Putting the wrong fuel in your car is much more common than you would think and is equally common for both sexes so first off, don’t be too embarrassed as you have company.

Damage caused to your vehicle and subsequent action required will depend on the volume of wrong fuel in your car and the type of fuel which you have mis-fuelled with.

These factors will by default also determine the financial cost from misfuelling and the time needed to deal with it.

Putting diesel in a petrol car is far harder mistake to make than petrol in a diesel car because the diesel fuel nozzle is manufactured much larger than its counterpart. Basically, the nozzle doesn’t fit in the fuel tank of most petrol cars. Misfuelling with diesel in a petrol car is therefore a far less common misfuelling scenario.

This is not always the case though and diesel in a petrol car is not completely unheard of. In the eventuality that you have put diesel in petrol, then starting the car after having misfuelled could cause the spark plugs and fuel system to clog up causing misfire and smoking. If a substantial quantity of wrong fuel has been put in the tank then the circulating wrong fuel could cause the car to stop running altogether.

What quantity of diesel in petrol will require me calling a misfuelling specialist?

Misfuelling with 2l or less of diesel in a petrol car (proportionate to 5% or less of a completely full fuel tank) may well be a mistake that you could rectify yourself. As soon as you realise you have put the wrong fuel in your car, continue to fill the remainder of your tank with Petrol. There should be no need to call for assistance from a misfuelling specialist to have the fuel tank drained and you should be able to proceed without any damage to your car.

Misfuelling in excess of 5% of a full tank with diesel in a petrol car will unfortunately lead you to need assistance from a wrong fuel specialist. If you haven’t started the car yet then keep the engine switched off. If you have already started the engine with the wrong fuel in your car, then switch it off immediately you realise and call a professional misfuelling recovery service such as Auto Fuel Fix for assistance. Their fuel drain specialist will completely drain the wrong fuel from your car and give you an indication of what measures you should take following the fuel drain to prevent further damage. You should be on your way fairly quickly once the wrong fuel specialists arrive and the fuel drain can usually be done in situ. Fuel drain specialists like Auto Fuel Fix are generally available 24/7.

Petrol in a Diesel Car

Momentary lapses in concentration could easily lead to you having misfuelled with petrol in a diesel car. It is the most common wrong fuel error and with more and more diesel cars being sold year after year, it is becoming ever more common. The neck of a diesel car is generally bigger than that of a petrol car (hence why it is harder to misfuel with diesel in petrol). Petrol in a diesel car however is an easy fit!

Misfuelling with petrol in a diesel car can be slightly more problematic than diesel in a petrol car. The type of diesel engine you have, the quantity of wrong fuel you have put in and whether you noticed the mistake before starting the engine can all have an impact on the outcome of having put petrol in your diesel car. Because of their different viscosity, fuel systems seals and pumps can become damaged as the wrong fuel travels through the cars fuel system if you start the car with the wrong fuel in it.

Clear indicators that you have misfuelled with petrol in a diesel car which you may notice are:

  • A noisy rattling sound
  • Smoking
  • Non-starting

If you notice any of these symptoms and realise that you have misfuelled, turn your engine off immediately. This could minimalize any further damage.

What quantity of petrol in diesel will require me calling a misfuelling specialist?

10% or less of a full tank of petrol in a diesel car (5l or less), providing you completely fill your fuel tank with the correct fuel as soon as you realise, should be little enough to avoid the need to call a wrong fuel specialist.

Excess of 10% petrol in a diesel car could unfortunately, be more problematic, particularly if you have started the engine or driven the car.

In this circumstance, you will need to call a reputable wrong fuel specialist such as Auto Fuel Fix who will attend your vehicle wherever it is and fully drain the fuel tank of the wrong fuel to enable you to be on your way. After putting petrol in a diesel car, it is advised that you change your fuel filters at a sooner date than usual as they could be affected by misfuelling. You shouldn’t notice any ill effects or subsequent damage to your car following the fuel drain provided that you have not started the engine after you misfuelled as the wrong fuel will not have circulated the fuel system.

ORIGINALLY PUBLISHED ON

in

Cars

Photo of author

Faisal

Faisal is the cofounder and automotive photographer at Unfinished Man. He provides insider perspectives on the latest rides through his acclaimed photography. Faisal also serves as the site's watch expert, staying on the pulse of emerging timepieces. His seasoned eye for men's lifestyle products makes him an authoritative voice.

Leave a Comment