Positive Crankcase Ventilation: Testing and Inspection

Crankcase Ventilation System Inspection/Diagnosis (LTG)

Special Tools

EN 23951 - Valve Manometer

For equivalent regional tools, refer to Special Tools Special Tools.

1. Verify clean air cleaner.

2. Verify oil fill cap is in place.

3. Verify oil level indicator is installed.

4. Remove the oil level indicator. Install a EN 23951 - valve manometer or equivalent, into the oil level indicator hole.

5. Start the engine.

6. Check for slight vacuum. The vacuum level should be less than 3.377 kPa (1 in Hg).

7. If vacuum is higher, inspect and verify that the clean air hose from cam cover to air intake is not blocked or kinked.

8. If vacuum is in the normal range, remove the PCV line from the fresh air valve near oil fill cap. Block fresh air valve and also plug the fresh air hose. Vacuum should increase on the manometer. If held too long, vacuum will be drawn through the crankshaft seals creating a sucking sound.

9. If vacuum does not increase, the orifice in the camshaft cover assembly could be plugged. The valve is between the camshaft cover assembly and the cylinder head assembly.

10. If there is zero vacuum or pressure, verify compression of the engine.

11. If compression is normal, check for a blocked orifice at the camshaft cover assembly. Clean the orifice.

12. The hose from valve cover to the turbo is also for the positive crankcase ventilation (PCV) and is used for PCV flow under normal operation and only PCV flow during turbo boost conditions. If the hose is plugged, replace the PCV hose assembly and PCV fitting assembly at the turbocharger.