According to Edmunds.com, the easiest way to determine a car's engine size based on its Vehicle Identification Number is to use a VIN decoder such as the one found on VINDecoder.net. Each of the 17 digits in a VIN corresponds to a specific attribute of the vehicle.
The eighth digit in the VIN is the engine code, which provides details about the type, size and displacement of the engine, as well as where it was made. The VIN also provides information about the vehicle's country of origin, model type, trim level, body style and brake type amongst other things.
There are two different VIN standards: the North American VIN system and the International Standard ISO 3779 system, which roughly correspond to one another. The first three digits in the VIN are the manufacturer identifiers, with the first digit stating the country of origin. The second digit states the manufacturer and the third the division that produced the vehicle. For instance, if the second and third digits are GI, it means that the Chevrolet division of General Motors produced the vehicle.
In North American vehicles, the fourth through eighth digits list the vehicle attributes, while the ninth digit is a check digit used to determine invalid VINs based on a mathematical formula. The tenth digit is the year of manufacture, and the eleventh is the factory code. The last six digits are the plant sequential numbers, which show when the vehicle came off the assembly line.