Topping up your fuel tank with the wrong kind of fuel - this is in fact an honest and common mistake. Human beings are prone to mistakes. However, the chances of filling up a petrol engine with diesel is not very common. The main reason being the advantage that petrol cars have in terms of the refilling nozzle size. Petrol cars’ tanks generally have a smaller opening and thus the nozzle of the diesel dispenser does not fit into it. However, misfuelling a diesel car is easier and common as well. But what happens when we fill a diesel car with petrol, or a petrol car with diesel?
The major problem lies in the working mechanism of the engines. Diesel engines use the fuel to lubricate the internal parts of the engine and this mechanism strikes a major problem. The petrol gushes into the internal parts of the diesel engine as per the mechanism. Plus, petrol does not have any lubricating capacity and thus it will cause extensive damage to the engine.
What Are The Consequences Of Misfuelling?
Irrespective of the possibilities of misfuelling, both the incidents (petrol in diesel car or diesel in petrol car) can damage your engine. Let us consider the following scenarios:
Scenario-1: Diesel in petrol car
Given the nozzle of petrol car tanks are smaller than the nozzle of a diesel dispenser, the chances of misfuelling is curtailed to a great extent. Nevertheless, in case a petrol car is topped up with diesel, the chances of damage is quite minute. Petrol is much more refined than diesel and thus, it is ignited by the spark created by spark plugs. If a petrol car is cranked with diesel in its tank, the spark plugs and fuel system will be clogged by the diesel. The fuel filter is one of the first parts to be affected because fuel filters in petrol engines are not used to the greasy property of diesel. These will lead to misfiring of the engine, heavy smoke from the exhaust, and will possibly stall the car.
Scenario-2: Petrol in diesel car
This is definitely an unfortunate mishap and might cause large-scale damage to the engine. As the petrol dispenser nozzles are smaller, it becomes easier to misfuel a diesel car. Unlike petrol cars, diesel engines compress the fuel to ignite and the fuel is pushed into the internal parts of the engine to lubricate them. The problem starts here. It is hard to get rid of the petrol which is circulated in the integral parts of the diesel engine. The proper functioning of the fuel injection pump is dependent on the lubrication property of diesel. Since petrol cannot perform that job, the performance becomes uneven. The worst part is it takes some time to realise misfuelling in diesel cars and by the time you realise the mistake the car will start gushing out black fumes through the exhaust pipe and will tend to move sluggishly and finally stop.
What can you do if you have filled wrong fuel in my car?
It is important to handle a misfuelling situation as soon as you realise it. Here is what you can do in each of the above-mentioned scenarios.
Diesel in petrol car:
As mentioned above, the first scenario is not as unfortunate as the second one. So, in case you have topped up your petrol car with diesel you can follow the following steps to ensure that you do not suffer because of that:
- If you realise while filling up: This will act as a boon for you. If your car’s tank is filled up with diesel for less than 5% of the total tank capacity, you can fill up the rest with petrol and drive your vehicle normally. Diesel easily mixes with petrol and thus there should be no problem in this case. However, it is recommended to fully drain the diesel to avoid any contamination at all.
- Realising after the fill-up: The situation is still under control. In cases where more than 5% of the tank’s capacity is filled with diesel, it is very important to not crank the engine. Instead you can call for a tow service and take the car to a nearest workshop. Drain the diesel completely and flush the fuel tank. Once the tank is empty and flushed thoroughly, you can fill it up with petrol again and your car will be good to go.
- If you have turned your engine: In case you have ignited the engine, turn it off as soon as you realise. Drain off the fuel tank and flush the tank and fuel line thoroughly with clean petrol. After the process is completed, you can refill your car with petrol and get going without any further complication.
- If you have driven the car for some time before realising: This is the worst-case scenario. Stop your car as soon as possible and turn the engine off. You can consider calling a roadside assistance service or a towing service to tow your car to the nearest workstation. Get your car’s tank and fuel lines flushed to get rid of residual contaminated fuel. You can refill your car with petrol again and drive without any problem. However, as a precautionary measure, you can get your fuel filter changed as early as possible.
Petrol in diesel car:
Diesel cars are not as forgiving as their petrol counterparts. If the ignition is turned on with the wrong fuel in the tank, there are high chances that you would end up with a hefty bill. The sole reason is that as soon as the engine is turned on, the petrol gushes into the internal parts of the engine which need lubrication to work properly. In case you end up filling up your diesel car with petrol, here is what you can do about it:
- Do not turn the engine on: No matter what happens, if you get to know that your diesel car has the wrong fuel in its tank, do not crank the engine. As long as the fuel is in the tank and the engine is not turned on, your car is out of danger. Get your car towed to the nearest workstation and with the assistance of a professional mechanic, get the tank evacuated. Once the tank and main fuel line are flushed, you can fill up your car with diesel again and can consider adding an additive to clean the injectors. Note: Cars with automatic transmission systems will pump oil into the system even if the key is turned to the ignition slot to shift the car to neutral.
- If you have driven the car for some time before realising: Perhaps, this is the most unfortunate incident. If you have driven your diesel car with petrol in its tank for a period of time, it is highly likely that the petrol has been pushed to every corner of the engine. Stop your car and turn off the engine as soon as you realise the blunder and get a roadside assistance or tow service to take your car to the nearest authorised service centre. Get a professional to work on your car. The bill you would have to pay in this case will depend on the extent of damage caused to the engine.