Formula to convert 5.1 liters to gallons is to multiply 5.1 by 0.264172 (this is the value for 1 liter to gallon).
Convert 5.1 Liters to Gallons results
5.1 x 0.264172052 = 1.34727746724
5.1 l = 1.35 gal
To conclude the answer for 5.1 liters is one point thirty five gallons