look on the back of the car, on the trunk lid. on the drivers side, you will see the word "SENTRA" in gray letters. in the middle, you'll see a nissan emblem. :thumbup: on the passengers side, you will see the model - SE, XE, E, Limited Edition, SE-R, etc. if there's no model, it's probably a bottom-of-the-line model that came standard with 4 tires and a heater. nissan played with the sentra's features for a few years.
unless it's an SE-R, you will have the GA16DE. it's still a powerful little motor.
Dan