Automotive Experts Warn Against DIY E10 Fuel Blends and Unverified Additives Amid E20 Rollout

As the rollout of E20 fuel continues at petrol pumps, vehicle owners are expressing concern over potential mileage reductions and mechanical issues in older cars and two-wheelers that were not originally designed for the fuel. In response, motorists have begun turning to social media recipes suggesting the manual mixing of regular E20 with expensive 100-octane petrol to recreate E10 blends. Additionally, direct-to-consumer (D2C) brands are marketing various fuel additives promoted as 'E20 enhancers' to promise better mileage and protection.

However, industry experts caution that these DIY workarounds are not safe or reliable shortcuts. Randheer Singh, former Director of Electric Mobility and Clean Energy at NITI Aayog and Founder and CEO of ForeSee Advisors, noted that manual fuel blending is not a simple process. Attempting to dilute E20 with premium petrol requires precise tracking of the fuel already in the tank, the ethanol content of the added fuel, and exact quantities. Inconsistent mixing can result in the vehicle repeatedly receiving fluctuating ethanol concentrations, such as E5, E10, E15, or E20, making it difficult to trace the root cause of subsequent mileage drops, misfires, or mechanical faults.

Similarly, Singh advised against using unverified additives sold by D2C brands to counteract ethanol issues. Introducing unvetted chemical mixtures into modern BS-6 fuel and emission systems can lead to significant mechanical problems. Motorists have been advised to use strictly manufacturer-recommended additives or those specifically validated for fuel compatibility.

For owners of older vehicles, the recommended approach begins with verifying the fuel-lid label, consulting the owner's manual, and checking the manufacturer's latest guidance for the specific vehicle model and year. If compatibility remains uncertain, owners should contact the manufacturer directly.

For infrequently used vehicles, additional precautions are advised. Because ethanol attracts moisture from the air, owners are advised to keep fuel tanks reasonably full—around 60 percent or more—when a vehicle is parked for extended periods to minimize empty space where condensation can form. Furthermore, fuel caps and seals should be maintained in good condition, and any unusual fuel smells or seepage should be investigated promptly.

Experts emphasize that a single tank of poor fuel does not automatically equate to ethanol damage, as water contamination, a tired fuel pump, a clogged filter, or an ignition fault can produce similar symptoms. If vehicle issues persist across multiple fuel refills, owners are advised to seek a proper diagnosis at an authorised workshop rather than relying on homemade fixes or unverified online cures.

"The emergence of DIY fuel blending and D2C additives highlights a clear consumer anxiety regarding infrastructure transitions like the E20 rollout. From a business and consumer perspective, improvising with fuel chemistry introduces severe risks to vehicle longevity and warranty compliance. Entrepreneurs and brands in the D2C space must prioritize regulatory compliance and scientific validation rather than capitalizing on short-term market fears with unverified products. Motorists should stick strictly to OEM guidelines and professional maintenance." — Dr. Shishir Gupta, Founder & CEO, StartupLanes