They were 3 models made; The passat GLX with a 2.8 engine, the passat TDI with a 1.9 engine and the passat variant with a 1.6, 1.8 2.0 2.3 2.8 and 2.9 engine.
There were two models of the 1997 VW Passat manufactured. They were 4 door sedan models, the TDI and the GLX models. The main difference in the models was the TDI was diesel powered and the GLX was gasoline powered.
It was available as a 4-door sedan or 5-door station wagon. For America, it was available in 3 trim levels; a 2.8 liter V6 gasoline engine, a 2.0 liter I4 gasoline, and a 1.9 liter TDI diesel.
In 1997 VW passat's were all made with the same engines, but like many cars I know that there are only a few difference between the trims. Such as the more expensive models came with leather seats and sunroofs, while the base cheap models came with cloth seats and no sunroof.
This is a fairly broad question becomes there are many different models of your type of car. I would either consult a mechanic personally, or refer to your user manual.
