The drive belt system consists of the following components:
|     •  | The drive belt tensioner | 
 
|     •  | The drive belt idler pulley | 
 
|     •  | The crankshaft balancer pulley | 
 
|     •  | The accessory drive component mounting brackets | 
 
|     •  | The accessory drive components | 
 
|        -  | The power steering pump, if belt driven | 
 
|        -  | The A/C compressor, if equipped | 
 
|        -  | The engine cooling fan, if belt driven | 
 
|        -  | The water pump, if belt driven | 
 
|        -  | The vacuum pump, if equipped | 
 
|        -  | The air compressor, if equipped | 
 
The drive belt system may use 1 belt or 2 belts. The drive belt is thin
so that it can bend backwards and has several ribs to match the grooves  in
the pulleys. There also  may be a V-belt style belt used to drive certain
 accessory drive components.  The drive belts are made of different types
of  rubbers -- chloroprene or EPDM -- and have different layers
or  plys  containing either fiber cloth or cords for reinforcement.
Both sides of the drive belt may be used to drive the different accessory
drive components. When the back side of the drive belt is used to drive a
  pulley, the pulley is smooth.
The drive belt is pulled by the crankshaft balancer pulley across the
accessory drive component pulleys. The spring loaded drive belt tensioner
      keeps constant tension on the drive belt to prevent the drive belt from
  slipping.     The drive belt tensioner arm will move when loads are applied
  to the drive     belt by the accessory drive components and the crankshaft.
The drive belt system may have an idler pulley, which is used to add
wrap to the adjacent pulleys. Some systems use an idler     pulley  in place
 of an accessory drive component when the vehicle is not equipped      with
 the accessory.