One little known (and yet, not surprising) quirk of Singaporeans is that our motorists have a firm belief that physically rocking their cars while fuelling up maximizes the flow of petrol by ensuring that the tank gets filled up to the fullest. The method consists of sloshing around petrol in the tank to get rid of any air bubbles, thus ensuring that you get every single drop of fuel inside.
So you can understand why its a phenomenon usually mocked by Malaysians when they see Singaporeans in their petrol stations doing so to get that money’s worth of petroleum — already way cheaper than what it would cost to fuel up in Singapore. Plus, the motorists just look really silly doing it.
We’re happy to report that the stunt is also carried out in Singapore as well, as seen in this video uploaded on the District Singapore Facebook page — perhaps the goofiest version of the technique we’ve seen so far. Let’s just say that this was not the motorist’s classiest moment. The exact location of the Esso petrol station and when this took place is unknown.
Does it really help though?
As Malaysian publication SAYS noted out in a piece about the uniquely Singaporean phenomenon, shaking or tilting cars do help in ensuring the tank gets filled up to its maximum capacity — but there’s a reason why we’re not supposed to. The extra pocket of air in the tank is a safety feature meant for space when fuel expands as it gets hot. If the tank is filled to its maximum capacity, flammable vapor could leak out and pose a fire risk. Overfilling the gas tank could damage car engines too when liquid fuel enters the charcoal canister or carbon filter — both of which are designed only for vapor.
Take it from this dude who answered a question on Quora.