Is Ethanol blend in petrol damaging your vehicle? Govt pushes for it, manufacturers sound caution

While some of the newer vehicles have been designed with hardened seals, ethanol-resistant components and upgraded engine control units (ECUs) to support E20, the majority of the existing vehicle fleet remains vulnerable. Manufacturers have requested the government to adopt a phased approach and greater transparency in rollout to protect consumers from unintended consequences of the blended fuel added to their vehicles.

The on-ground situation seems to echo the manufacturers' point of view as several vehicle owners have reported a wide range of issues after using the E20 that has been made available at petrol pumps across the country.

Complaints related to lower mileage, increased engine knocking, rough idling and performance-related issues have skyrocketed with the use of E20. Reports have also said that the lack of fuel labelling has been another problem since the consumer don't even know if their vehicles are being pumped with E10 or E20 and in some cases, the consumers would be filling up their vehicles using E20 even involuntarily.

Reports have quoted experts sounding the alarm, saying that the usage of E20 without the vehicles being ready for it could do far greater harm than good. Ethanol-compatible fuel systems require upgraded materials which include anti-corrosive treatments and engine remapping to ensure that optimal performance and safety of the vehicle is maintained even after switching to E20 blend.

Without these changes in a large sum of already on-the-road vehicles, forcing E20 into a could lead to widespread reliability issues and even road safety hazards. One of the main problems that comes with using ethanol is its low energy density. Ethanol provides roughly 33% less energy per unit volume than petrol, reports have said.

What happens because of that is that E20-blended petrol causes a significant reduction in fuel efficiency. Users have said that they sees an upto 4% drop in mileage as a result of using E20. The effect is more visible in older vehicles that have E10-caliberated engines which are not used to carrying the E20 load.

Ethanol is also a hygroscopic material, which means that it readily absorbs water from the atmosphere. This can often lead to corrosion in metal fuel tanks and fuel system components.

Ethanol is also known to degrade plastic and rubber parts more quickly than petrol does and this could cause problems with fuel leaks, degraded gaskets, clogged fuel injectors and more.

A report by South First quoted several users voicing their concerns over E20 usage. "I own a 2022 Maruti Suzuki Brezza, I definitely have noticed- mileage has dropped sharply to around 14km/L from the previous 17-18 km/L and also sluggish pickup. It’s a relatively new model, the fuel efficiency has reduced, and the car feels less responsive. This is a classic sign of ethanol blending,” Akanksha Bokdia, a public relations consultant in Chennai, told South First.

“I started using E20 petrol recently since it’s becoming more common at fuel stations, but honestly, I’m not very happy with how my car is performing. I drive a petrol sedan that’s a few years old — not one of the newer flex-fuel models — and I’ve noticed a clear drop in mileage. Earlier, I used to get around 16-17 km/l, but now it’s gone down by at least two to three km. Acceleration also feels a bit sluggish, especially with the AC on or while overtaking,” Subramaniam, a native of Thiruvananthapuram, told South First.