(An archive of a similar claim can be found here.)
We also received multiple queries on our WhatsApp tipline about the viral circular.
Are these claims true?: No, Indian Oil has not issued any such circular. The company has clarified multiple times on their social media platforms and termed the circular as "fake news".
We also spoke with an automobile engineer who confirmed that the auto-ignition is not possible without external factors.
How did we find out?: A keyword search led us to a post on the official Facebook page of Indian Oil Corporation Limited.
It was uploaded on 9 April 2022 and its caption mentioned that "it is perfectly safe to fill fuel in vehicles up to the limit (max) as specified by the manufacturer irrespective of winter or summer."
It carried the viral circular, which the company termed as "fake news".
Interestingly, the circular or the viral message gets often shared, and Indian Oil has issued multiple clarifications over the years.
The company also issued a clarification on their Twitter handle in June 2018.
It mentioned that vehicles are designed considering "all aspects of performance requirements, claims, and ambient conditions with built in safety factors."
What do the experts say?:
The Quint spoke to Bani Kalra, automobile journalist with Rajasthan Patrika, who said, "The viral message is nothing but a rumour. The vehicle will not blast if the fuel tank is filled to the maximum limit irrespective of the weather (summer or winter)."
Viplove Pradhan, an automobile engineer, explained to The Quint how ignition happens in an automobile engine.
Gasoline or diesel ignition happens when the temperature reaches beyond the self ignition temperature through pressure or spark through spark plugs so as to ignite the fuel.Viplove Pradhan, Automobile engineer
He further said that the temperature in Indian summers reaches maximum up to 122-125 degree Fahrenheit which is not sufficient to ignite gasoline or diesel by itself.
A list of self-ignition temperature for various fuels can be found below.
What is self-ignition temperature?: Self or auto-ignition temperature is the lowest temperature at which a fuel or substance ignites itself without any external factor such as spark or flame.
Manufacturers recommend filling 15-20% less fuel than actual volume: According to a circular dated 6 March, Ministry of Consumer Affairs, Food and Public Distribution has advised people to not fill the fuel tank completely. This is because when a vehicle filled with full capacity is parked slantly then it might experience a leak which may lead to explosion.
However, it did not mention anything about the vehicle exploding in summers due to the filling of the tank to the maximum limit.
Conclusion: It is safe to say that the viral circular is fake. The claim stating that vehicles can explode due to filling the tank to maximum capacity in summers is incorrect.