COMPONENT LOCATION
| Item Number | Description |
|---|---|
| 1 | Part load breather |
| 2 | Full load breather |
INTRODUCTION
The engine emission control system reduces the level of hydrocarbon emissions released to atmosphere from the engine. The engine emission control system consists of a positive crankcase ventilation (PCV) system with part and full load breathers. Piston blow-by gases are drawn through the breathers into the engine air intake and added to the air charge. The resultant depression in the engine sump, front covers and cylinder head covers reduces the load on the joint seals in those areas.
PART LOAD BREATHER
| Item Number | Description |
|---|---|
| 1 | Flexible hose |
| 2 | Baffle plate |
| 3 | Oil drain |
| 4 | PCV (positive crankcase ventilation) valve |
| 5 | Oil separator |
The part load breather consists of an oil separator, two positive crankcase ventilation (PCV) valves and a flexible hose. The oil separator and the positive crankcase ventilation (PCV) valves are installed in the top of the right-hand (RH) cylinder head cover. The flexible hose connects the right-hand (RH) cylinder head cover to the inlet of the intake manifold.
The oil separator is installed in a channel in the top of the cylinder head cover. A baffle plate, which incorporates a gas inlet and an oil drain, is installed over the channel. The two positive crankcase ventilation (PCV) valves are installed on the outside of the cylinder head cover and connected in parallel in the gas outlet from the channel to the flexible hose. The positive crankcase ventilation (PCV) valves prevent reverse flow into the cylinder head cover when there is minimal depression in the intake manifold.
FULL LOAD BREATHER
| Item Number | Description |
|---|---|
| 1 | Flexible hose |
| 2 | Two-way valve |
| 3 | Oil drain |
| 4 | Baffle plate |
| 5 | Oil separator |
The full load breather consists of an oil separator, a two-way valve and a flexible hose. The oil separator and the two-way valve are installed in the top of the left-hand (LH) cylinder head cover. The flexible hose connects the left-hand (LH) cylinder head cover to the left-hand (LH) air duct of the intake air distribution and filtering system.
The oil separator is installed in a channel in the top of the cylinder head cover. A baffle plate, which incorporates a gas inlet and an oil drain, is installed over the channel. The two-way valve is installed in the gas outlet from the channel. The two-way valve prevents reverse flow into the cylinder head cover when there is minimal depression in the air duct.
PRINCIPLES OF OPERATION
For a detailed description of the engine emission system and operation, refer to the relevant Description and Operation instruction of the Workshop Information.
INSPECTION AND VERIFICATION
| CAUTION | Diagnosis by substitution from a donor vehicle is NOT acceptable. Substitution of control modules does not guarantee confirmation of a fault, and may also cause additional faults in the vehicle being tested and/or the donor vehicle. |
- Verify the customer concern.
- Visually inspect for obvious signs of mechanical or electrical damage. VISUAL INSPECTION Mechanical Electrical Engine breather hoses Oil separator Exhaust gas recirculation (EGR) pipes (check for cracks) EGR valve(s) EGR cooler(s) Fuse(s) Wiring harness Loose or corroded electrical connector(s) Intake manifold tuning (IMT) valve EGR valve(s) Engine control module (ECM)
- If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
- If the cause is not visually evident, verify the symptom and refer to the Symptom Chart, alternatively check for Diagnostic Trouble Codes (DTCs) and refer to the DTC Index.
SYMPTOM CHART
| Symptom | Possible Causes | Action |
|---|---|---|
| Difficult to start | EGR valve(s) stuck open | Check the EGR valve and circuits. Refer to the electrical guides. Check the mechanical condition of the EGR valves. Rectify as necessary. |
| Poor/Erratic idle | ||
| Lack of power when accelerating | ||
| Engine stops/stalls | EGR valve(s) stuck open Breather system disconnected/restricted/blocked | Check the EGR valve and circuits. Refer to the electrical guides. Check the mechanical condition of the EGR valves. Check the engine breather system. Check the oil separator. Check for DTCs indicating an EGR valve, throttle or sensor fault. Rectify as necessary. |
| Excessive fuel consumption | EGR valve(s) stuck open EGR not operating Breather system restricted/blocked | |
| Excessive black smoke | ||
| Excessive emissions | ||
| Excessive blow-by | Breather system restricted/blocked | Check the engine breather hoses. Check the oil separator. Rectify as necessary. |
| Engine oil leaks | Breather system restricted/blocked | Check the engine breather hoses. Check the oil separator. Rectify as necessary. |
DTC INDEX
For a list of Diagnostic Trouble Codes (DTCs) that could be logged on this vehicle, please refer to Diagnostic Trouble Code (DTC) Index - 5.0L, DTC: Module Name: Engine Control Module .