It's the belt for the water pump.
It depends on the year model of the car and the engine that you have.
Need to know make and model of engine in order to answer this.
I don't have the exact car model diagram but try this http://www.gti-vr6.net/library/engine/repl_serpentine_belt_NEW.html
Sorry, no make, no model, no engine size, and no year equals no answer.
The year, make and model would help us help you.
Need an engine make and model to answer this. You either have a Detroit Diesel, Mercedes Benz, Cummins, or Caterpillar engine.
beside the engine
A serpentine belt has a specific length according to the make and model of the engine to which it is fitted. Its purpose is to drive additional features on the engine, such as the water pump, alternator etc. Bypassing any of these auxiliaries would mean the engine would not function correctly and ultimately would damage the engine perhaps beyond repair.
As you listed no make, model, engine, or year, all I can say is look under the hood for a placard diagram. Usually there is one there.
Please rephrase your question... you either have the model year wrong, or you don't realize what you have is an N14 engine.
The water pump on this model is located on the top of the engine to the side with the serpentine belt. Its pulley will be the one with the smooth wheel
The SERIAL NUMBER of a GIBSON Model D is stamped into the top of the frame rail, directly beside the engine mount on the left-hand side of the tractor.