What to do if you put the wrong fuel in your car

By: Lisa Keegan

Date: Wednesday, 02. June 2010

putting wrong fuel in car You pull into a gas station late at night, tired and in need of fuel for both yourself and your car. You grab a coffee from the machine and proceed to fill up your gas tank to get you on your merry way. While pumping the fuel into your car you take a gulp of the coffee to waken the senses but disappointedly realize that you have pressed the �decaf� button in error. A bit of an inconvenience but this mistake is only going to cost you the price of another cup of coffee. At that moment you realize the pump nozzle you are holding is for Gasoline but your car is Diesel - this mistake could cost you a lot more than a coffee refill...

So what do you do now?

Stop pumping the fuel
Assess how much of the wrong fuel you put into the tank (is it more or less than 10% of the tank capacity?)
Don�t start the engine (if you need to move away from the pumps, push the car to a parking bay)

If you've put the wrong fuel in your car, don't turn on the ignition or start the engine as this could compound the mistake by circulating the contaminated fuel and increasing the risk of damage to your car.

The �Gasoline in Diesel� mistake is a far more common scenario than the reverse. This is because the Diesel nozzle is much bigger than Leaded Gasoline nozzles which are thus unable to fit in the gas tank of most cars (with the exception of some older models). The Unleaded and Leaded Gasoline nozzles are also different sizes with the Unleaded being the smallest - the use of the wrong fuel in an Unleaded car is therefore the least likely scenario to come across.

On discovering you have put the wrong fuel in your car, the first thing you should do is check with your local dealer on what action to take (if your car is still under warranty). The dealer may advise towing the car to a garage and having the tank drained and the seals and filters changed. If you take action yourself or even start the engine after using the incorrect fuel, you may invalidate your warranty.

Assuming your car is out of warranty or you have been given the go-ahead by your local dealer, here is what to do next.

If you've pumped more than 10% of your tanks capacity with the wrong fuel (Gasoline in our example) you will need to drain the tank and refill it with Diesel.

If you've added less than 10% Gasoline then top up with Diesel and run normally unless you have received advice to the contrary from your local dealer or manufacturer.

The main damage in mis-fueling cases is caused, not by the act of pumping the wrong fuel into the tank, but of starting the engine and driving away. Diesel is obviously a propellant but it is also used a lubricant for components. The solvent nature of Gasoline can strip out the lubricant and cause metal components to grind together. This is where the damage can become very expensive if you accidentally put Gasoline into a Diesel car.

Putting the wrong fuel in your car is not an uncommon mistake and certainly not uniquely American. In 2008 a UK newspaper reported that there are �an estimated 120,000 drivers put the wrong fuel in their car every year - about 13 an hour - and end up paying out a total of �50 million in repair bills.�

Related Links:

How to drain your car's gas tank

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All Comments (4)

Showing 1 - 4 comments

Rene,

If I put Ethanol 85% ethanol gas, in my gas tank, what can happen? Should I stop and get it to a mechanic to fix drain tank and re-fill? Vehicle type is: Honda CR-V 2008

AGIDI OLUSOLA DANIEL,

As a matter of fact, it is an uncommon mistake to fill a wrong fuel into your vehicle tank.
Usually, some drivers are gdug adict, so they easily loose there senses, the aldo fail to obserse traffic rules and contribute to traffic scratches on the road.

jollon john,

why should diesel be pumped into the fuel tank unlike the gasoline which can be poured gently?????

Alex,

my car is broken and you where right.