Petroleum dealers are cautioning customers about water seepage in fuel tanks of their vehicles.

The increased presence of ethanol (limit raised from 5 to 10 per cent) in petrol attracts water because of its hygroscopic property, which often stalls cars and creates jerks while vehicles are in motion.

In 2019, especially during the monsoon, a number of such complaints had arisen where vehicle owners alleged that fuel pumps were mixing water with the fuel. Auto workshops reported several cases of water-petrol mix in June, July and August.

Fuel pump owners are now telling their customers to ensure that no water gets into their fuel tanks because that will mix with ethanol and create layers of impurity in the petrol, leading to engine damage.

Ethanol attracts water and creates distinct layers and settles down at the bottom of the fuel tank. Fuel pump owners are also saying that customers will be solely responsible if water is found in their vehicle’s fuel tank.

The West Bengal Petroleum Dealers Association is carrying out an awareness drive through social media and hoardings at petrol pumps and also talking to customers coming for refills.

“We are carrying out the awareness drive well ahead of the monsoon season, when there are a number of cases where vehicles stall because of this issue,” said Tushar Kanti Sen, the president of the association. “Earlier, when ethanol content in petrol was five per cent, few such cases of petrol-water mix happened. But now since the ethanol content has risen, petrol is prone to getting mixed with water. And since customers are not aware of this, they tend to blame petrol pump owners for having mixed water with petrol.”

Vehicle owners tend to wash their vehicles with water, which may lead to water seepage into fuel tanks. “Vehicles should only be wiped and not washed,” said Sandip Banerjee, a manager at a workshop.

Recently, at a vintage car rally, a WhatsApp message from the Petroleum Traders Welfare & Legal Service Society was circulated among the participants.

The message read: “Motorists are advised to exercise care so that water does not come in contact with petrol. This may happen during routine car washing or during rains…. We, petrol dealers, are taking extreme care in this regard and the same is advised for the motoring public.”

The awareness message also advised customers to check the quality of petrol from the nozzle of the dispenser at the retail outlet. It warned: “Water found in the tank of a customer's vehicle is his responsibility.”