With the rising number of cars on the road, the problem of filling the wrong fuel is not so uncommon. Last year, an MLA from Karnataka became the latest victim of filling the wrong fuel when the fuel attendant put diesel in his Volvo XC90 Hybrid, which is a petrol powered SUV. Such oblivious situations do happen a lot and car owners should be extra-cautious when filling fuel. But what to do if such slip-ups happen?
Know the signs
The modern engines are very sensitive and will respond strongly if the wrong fuel reaches them. If you have identified that the wrong fuel has been filled up in the vehicle at the fuel station itself, the first step is to not start the vehicle at all. Let the vehicle be where it is or push it to the side and call for help. Service centres can take out the fuel tank and clean it thoroughly without damaging the engine. But what if you have not checked the bill and do not get to know about the wrong fuel at the fuel pump and start to drive the car?
Signs of diesel in a petrol car: Diesel fuel is stickier and thicker than petrol. The fuel properties make it stick to the fuel filter of a petrol car and it clogs up the fuel line completely. In such cases, you will notice that the engine will stall even if there’s enough fuel in the tank. However, if the diesel reaches the engine and the spark plug tries to burn it, there will be a thick white smoke from the tailpipe. Diesel fuel does not burn easily. It has to be pressurised before it catches fire. The engine stalls eventually after shudders and jerks.
Signs of petrol in a diesel car: Now diesel engines are not as simple as the petrol ones. They use complex mechanicals to inject the fuel inside the cylinder where it is pressurised so that it can burn. Petrol is highly inflammable and due to the complex nature of the diesel engines, the signs do not show up early. It takes quite a while and a few kilometres before the diesel engine starts emitting thick black smoke due to the unburnt fuel. There is no spark plug inside a diesel engine and petrol does not catch fire without a flame. The diesel engine becomes sluggish and stalls if one continues to drive it.
Can you make it right?
If you realise the mistake and stop the engine in time, the engine can be saved completely. In such cases, the mechanics drain the fuel tank and clean the main fuel line thoroughly. If the wrong fuel reaches the engine, the mechanic also cleans the engine parts by opening the engine completely. The cleaning process also includes cranking up the engine so that the wrong fuel in the crevices of the pistons come out.
In petrol engines, parts like fuel filter and spark plugs need to be changed. In diesel engines, the engine drain plug at the bottom of the engine compartment ensures that every last drop of the wrong fuel is out. After the cleaning process, one needs to fill up the tank with the correct fuel and usage of additives are adviced to help the engine to clean itself of any residue of the wrong fuel.