Wrong fuel: What you should keep in mind

Mixing up fuels when refueling can lead to expensive damage. The ADAC offers tips on how to react after a misfueling.

Confused about diesel and petrol? In case of doubt, this means a costly repair – if the engine or injection system is damaged, the costs can quickly reach four-digit figures. ADAC (General German Automobile Club) gives Suggestionshow to behave correctly after misfuelling.

The tips from the ADAC

What to do if...

... gasoline in the diesel tank?

This is probably one of the most common cases, as the fuel filler neck for premium petrol – provided the vehicle doesn't have a misfuelling protection system – also fits into the fuel filler neck of a diesel car. The ADAC advises: under no circumstances switch on the ignition! In addition, drivers of modern cars should If possible, avoid opening the driver's door, as some vehicles then already start the fuel pump and the wrong mixture is thus fed into the engine system. Instead, drivers should Observe the instructions in the vehicle manufacturer's operating manualIf the engine has not yet been started, it may be sufficient to Pumping the diesel-petrol mixture out of the tank.

But what if the Engine already running Naturally, diesel builds up a lubricating film, which is immediately removed by the petrol – then it can lead to a engine failure In addition, filling the fuel tank with AdBlue or fuel into the AdBlue tank often leads to expensive damage.

By the way: Very old diesel carsthat do not have direct injection are among the exceptions. They can handle a few liters of petrol compared to a comparatively large amount of diesel. 

... diesel in a petrol engine?

Although diesel pump nozzles at gas stations have a larger diameter than the filler necks on gasoline-powered cars, the nozzle can often be inserted into the filler neck. If it hooks into place, refueling with diesel is possible. The following also applies here: Do not open the driver's door, do not switch on the ignition, do not start the engine and consult the operating instructions.

In older vehicles, a small protective flap was often installed in the rear area of ​​the filler neck; nowadays this is rarely the case.

... Super E10 instead of E5?

This is usually not a problemAlmost all vehicles built since 2011 are approved for this fuel. However, if the car is not approved for E10, the Instructions from the vehicle manufacturer Often it is sufficient to simply Fill the tank immediately with a low-ethanol variety – ideally Super Plus.

ADAC on YouTube: Wrong fuel in the tank

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And who bears the costs?

For the Costs of pumping of the wrong fuel or the possible Engine repair must the Consumers usually pay themselvesInsurers usually do not cover such cases.

As part of his Car tests The ADAC checks all test vehicles to see whether it is possible to misfuel with petrol or diesel. Most new diesel models are now equipped with misfuelling protection, while petrol models often lack this.

Source: ADAC

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