Section 3.12
Ventilating System

Vapors, formed within the engine, are removed from the crankcase, gear train and valve compartment by a continuous pressurized ventilating system.‪

A slight pressure is maintained in the engine crankcase by the normal seepage of a small amount of air and combustion gases past the piston rings. These gases are swept up through the engine and pass through a crankcase breather. On vehicle engines the gases are then vented to the atmosphere.‪

Breather extension hoses may be required on certain Series 60 engines used in on-highway vehicle applications. Under certain conditions, the vapors from an operating engine may be circulated through the battery charging alternator by the alternator cooling fan. Excessive ingestion of vapors may lead to alternator malfunction. This can occur if the internal components of the alternator become coated with oil-laden dust or road grit.‪

To minimize the potential for this condition, check the length of the engine breather tube and add an extension hose, if necessary. For proper dissipation of vapors, the end of the breather hose must extend at least 12 inches below the oil pan rail.‪

A wire mesh element is located inside the valve cover, or in a separate housing on the valve cover cap or at the gear case cover. This element traps excess engine oil particles in the vapor and returns them to the crankcase. See Figure "Wire Mesh Elements" .‪

Note: The Series 60G automotive engine uses a closed crankcase breather system. Refer to "6.4 Closed Crankcase Breather for Series 60G Automotive Engines" for more information.

Figure 1. Wire Mesh Elements

The former baffle, installed on engines between 6R128446 and 6R134254, has been replaced with the current baffle to redirect oil splash from the rocker arms. This prevents oil from contaminating the breather element.‪

Section 3.12.1
Repair or Replacement of Ventilating System

To determine if repair is possible or replacement is necessary, perform the following procedure. See Figure "Flowchart for Repair or Replacement of Ventilating System" .‪

Figure 2. Flowchart for Repair or Replacement of Ventilating System

Section 3.12.2
Removal of Ventilating System

Precleaning is not necessary.‪

Remove ventilating system as follows:‪

1. Remove the valve cover. Refer to "1.6.2 Removal and Cleaning of One-piece Rocker Cover For Diesel Engines Only" for one-piece, refer to "1.6.3 Removal and Cleaning of Two-piece Rocker Cover For Diesel Engines Only" for two-piece, and refer to "1.6.5 Removal and Cleaning of Three-piece Rocker Cover" for three-piece rocker cover.
2. If the engine is equipped with a gear case cover breather, remove as follows:
   1. Remove the five bolts that secure the breather-oil fill housing to the gear case cover. See Figure "Breather-Oil Fill Housing Bolt Location" .
   

   Figure 3. Breather-Oil Fill Housing Bolt Location

   2. Remove the three bolts that secure the retainer to the housing. See Figure "Gear Case Cover-Mounted Breather Housing" .
   

   1. Breather Housing‪	4. Bolts (3)‪
   2. Wire Mesh Element‪	5. Bolts (5)‪
   3. Retainer‪	‪

   Figure 4. Gear Case Cover-Mounted Breather Housing

   3. Remove the retainer and wire mesh element from the breather housing.
3. If the engine is equipped with a breather mounted on the housing, remove as follows:
   1. Remove the three screws, baffle, and end retainer on the breather housing. See Figure "Breather Housing-Mounted Breather" .
   

   1. Two-piece Valve Rocker Cover‪	6. Baffle‪
   2. Retainer Clip‪	7. Retainer‪
   3. Wire Mesh Element‪	8. Rocker Cover Cap‪
   4. One-piece Rocker Cover‪	9. Seal‪
   5. Screws‪	10. Breather Housing‪

   Figure 5. Breather Housing-Mounted Breather

   2. Remove the breather housing seal and wire mesh element.
4. If the engine is equipped with a valve cover mounted breather, remove as follows:
   1. Press the center of the spring steel retaining clip outward and disengage the straight end from the valve cover. Rotate the clip upward and remove clip.
   2. Remove the wire mesh element from the valve cover.

Section 3.12.2.1
Inspection of Ventilating System

Inspect the ventilating system as follows:‪

1. Inspect the ventilating system for damaged parts.
2. Check components for pinched, broken, worn, and unclean parts.
   1. If any components are damaged, replace with new parts.
   2. If components are not damaged, reuse the parts.

Section 3.12.3
Cleaning the Ventilating System

Clean the wire mesh element components prior to inspection as follows:‪

1. Wash the components in clean fuel oil.

   EYE INJURY ‪
   To avoid injury from flying debris when using compressed air, wear adequate eye protection (face shield or safety goggles) and do not exceed 276 kPa (40 psi) air pressure.‪

2. Blow dry with compressed air.

Section 3.12.4
Installation of Ventilating System

Install the ventilating system as follows:‪

1. Install the gear case cover mounted breather as follows:
   1. Install the wire mesh element in breather housing.
   2. Install the three screws and retainer to breather housing. Torque the screws to 2.5 N·m (22 lb·in.).
   3. Install new gasket, breather and oil fill housing and five bolts on gear case cover. Torque bolts to 30-38 N·m (22-28 lb·ft), using the proper torque sequence. See Figure "Breather-Oil Fill Housing Bolt Location" .
2. Install the breather housing mounted breather as follows:
   1. Install the wire mesh element in breather housing.
   2. Install breather housing in valve cover.
   3. Install retainer on valve cover.
   4. Place the baffle on the retainer with three flat bolting flanges against the retainer.

   Note: The baffle must be installed with bolting flanges against the retainer to permit proper engine breathing.

   5. Install the three screws into baffle and torque to 2.5 N·m (22 lb·in.).
3. Install the valve cover mounted breather as follows:
   1. Install wire mesh element in valve cover.
   2. Install retaining clip in valve cover by engaging curved end in valve cover and then engaging straight end.
4. Install valve covers. Refer to "1.6.8 Installation of One-Piece Rocker Cover" for one-piece, refer to "1.6.9 Installation of Two-Piece and Three-Piece Rocker Covers" for two-piece or three-piece valve rocker cover.