Popular lifestyle YouTuber Sourav Joshi sparked widespread debate online after alleging that his Mercedes-Benz GLC SUV suffered a dramatic decline in fuel efficiency, which he attributed to the use of government-mandated E20 petrol. In a vlog that quickly gained traction on social media, Joshi claimed the SUV's mileage had dropped from around 16-17 kmpl to just 5 kmpl. He also voiced concerns about possible engine damage and said he faced the inconvenience of taking the vehicle from Haldwani to an authorised Mercedes-Benz service centre in Delhi.
The claims prompted an official response from Mercedes-Benz India, which sought to address growing concerns surrounding the compatibility of E20 fuel with its vehicles.
In a formal statement, the automaker reiterated that its latest petrol models sold in India are designed to operate on E20 blended fuel.
The statement reads, "The luxury manufacturer clarified that all of its modern vehicles sold in India are engineered to be fully compatible with E20 blended petrol. The statement reads, "At Mercedes-Benz, customer safety, vehicle reliability and performance are of paramount importance to use. All Mercedes-Benz petrol BS VI vehicles are materially compatible with E20 fuel and certified accordingly by elevant authorities. We are happy to support customers for any technical queries. Mercedes-Benz remains committed to sustainable mobility."
In the video, Joshi pointed to the SUV's digital instrument cluster as evidence of the sharp decline in fuel economy shortly after refuelling. While such a steep reduction in mileage would naturally raise concerns, attributing it solely to E20 fuel without technical verification does not provide a conclusive diagnosis.
Fuel efficiency in modern vehicles is influenced by numerous variables, including electronic sensor inputs, driving patterns, idling duration and surrounding operating conditions. A dashboard mileage reading alone cannot establish engine failure or confirm fuel quality as the cause without further examination, such as a physical inspection, fuel sample analysis or an On-Board Diagnostics (OBD) scan. Drawing conclusions about E20 fuel without an authorised technical assessment can also create unnecessary concern among vehicle owners.
Several factors can contribute to a noticeable increase in fuel consumption. Extended periods of idling, particularly in large-capacity engines running with the air conditioning switched on during filming, can significantly reduce the calculated mileage displayed by the vehicle. Similarly, frequent stop-and-go traffic, short city commutes and hilly driving conditions, such as those in Haldwani, generally result in lower fuel efficiency than uninterrupted highway driving.
Temporary issues related to electronic sensor calibration may also affect the fuel economy figures shown on the instrument cluster without necessarily reflecting the vehicle's actual fuel consumption.
It is also scientifically established that ethanol contains less energy per unit than pure petrol. As a result, vehicles operating on E20 fuel may experience a slight reduction in fuel efficiency, typically ranging between 1.5% and 3%.
A decline from 17 kmpl to 5 kmpl, however, amounts to an approximately 70% reduction in mileage. Such a substantial drop is more likely to indicate a significant mechanical or sensor-related fault, contaminated fuel, such as water entering a fuel station's storage tanks, or prolonged stationary idling, rather than the normal characteristics of E20 petrol.
The episode also highlights the importance of obtaining a professional technical evaluation when a vehicle exhibits unusual behaviour. For owners of premium vehicles, an authorised service centre is best placed to identify the underlying cause through systematic diagnosis before conclusions are drawn publicly.
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