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B5.9G, B5.9LPG – Troubleshooting and Repair Manual – 003-021   Crankcase Ventilation Filter

General Information

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Closed-Crankcase Ventilation System

  1. Blowby gas is evacuated from the crankcase via this hose
  2. Closed-crankcase ventilation unit
  3. Pressure regulator
  4. Filter
  5. Filtered gas is drawn into turbocharger air inlet due to inlet restriction from the air cleaner
  6. Oil filtered out of blowby gas is returned to crankcase
  7. Check valve
  8. Crankcase – gases blow by piston rings and accumulate here.

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Crankcase Ventilation System

  1. Inlet hose fitting
  2. Outlet hose fitting
  3. Plastic regulator body
  4. Diaphragm
  5. Seal
  6. Filter element
  7. Clasp
  8. Oil drain fitting
  9. O-ring
  10. Canister.

Crankcase vapors, or blowby gases, are gases that escape past the piston rings during engine cycling. These gases accumulate in the crankcase, and in an open system, vent into the atmosphere. Closed-crankcase ventilation incorporates a filter and pressure-regulator system. Blowby gases evacuate from the crankcase through a hose and travel toward the closed-crankcase ventilation unit. The unit then uses a pressure regulator to control crankcase pressure and a coalescing filter to remove the oil from the saturated crankcase vapors. The filtered gases return through the intake-air side of the turbocharger, while the filtered oil returns to the oil pan.

A crankcase pressure indicator is incorporated in the closed-crankcase ventilation housing. Once this pressure gauge reaches 0.515 in Hg [7 in H 2O], blowby gases begin to bypass the closed-crankcase ventilation filter. The closed-crankcase ventilation filter should be changed at a 6-month/28,968-km [18,000-mi] interval or when the pressure gauge reaches 0.515 in Hg [7 in H 2O], whichever occurs first.

Remove

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 WARNING 

To reduce the possibility of personal injury, avoid direct contact of hot oil with your skin.
 WARNING 

Some state and federal agencies have determined that used engine oil can be carcinogenic and cause reproductive toxicity. Avoid inhalation of vapors, ingestion, and prolonged contact with used engine oil. If not reused, dispose of in accordance with local environmental regulations.

NOTE: Refer to the Operation and Maintenance Manual, B5.9G (LPG Liquefied Petroleum Gas) Engines, Bulletin 3666213, for maintenance procedures.

Before removing the closed-crankcase ventilation unit, drain the excess oil from the canister to prevent spilling during removal.

Unscrew the oil drain fitting (1).

Disconnect the hose.

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Remove the hose clamps on both the breather inlet and breather return.

Disconnect the hoses.

NOTE: Be sure to notice the flow arrows on the closed-crankcase ventilation cap for proper unit orientation upon installation.

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Remove the two 10-mm bolts (1) from the closed-crankcase ventilation mounting plate.

Detach the closed-crankcase ventilation unit from the engine.

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Disassemble

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Undo the clasps (1) on the closed-crankcase ventilation canister.

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Pull the canister down to a point where the filter can be loosened.

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Remove both the filter and canister from the closed-crankcase ventilation unit.

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 WARNING 

Some state and federal agencies have determined that used engine oil can be carcinogenic and cause reproductive toxicity. Avoid inhalation of vapors, ingestion, and prolonged contact with used engine oil. If not reused, dispose of in accordance with local environmental regulations.

Empty any excess oil in the bottom of the canister.

  
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Assemble

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Replace the filter and o-ring on the upper stem of the filter.

NOTE: Be sure that the old o-ring has not been jammed within the closed-crankcase ventilation head before installing.

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Push the filter and canister back into position on the closed-crankcase ventilation unit.

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Fasten the clamps (1).

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Install

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Mount the closed-crankcase ventilation unit onto the mounting plate using the two 10-mm bolts (1) provided.

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Attach the hoses into their proper positions, and secure them with the provided hose clamps.

NOTE: Make sure to note the flow arrows on the closed-crankcase ventilation cap for proper unit orientation. Arrows pointing into the unit are for breather inlet plumbing. Arrows pointing out of the unit are for breather return plumbing.

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Screw the oil drain fitting (1) to connect the oil drain hose.

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Last Modified:  20-Jun-2005
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