VANOS Pressure Test

VANOS Pressure Test MSS65
The pressure test of the VANOS system checks the pressure generation and leak-tightness of the VANOS system.

Test preconditions:
- Engine at idle speed
- Engine oil temperature greater than 80° C

System overview:

VANOS Overview:

1) Connection to cylinder head
2) Banjo bolt for connection of the adapter and of the sensor
3) Connection to cylinder head
4) High pressure line in the crankcase
5) VANOS oil pump

Test procedure:
1. Connect the pressure adapter and the sensor to (2)
2. Measure the VANOS oil pressure
- If the oil pressure is OK:
No other measurement necessary, oil pressure in the system OK
- If the oil pressure is not OK:
Continue measurement with point 3
3. Loosen and close the high pressure lines at both cylinder heads, (1) and (3)
4. Measure the VANOS oil pressure
- If the oil pressure is OK:
Continue measurement with point 5
- If the oil pressure is not OK:
Check the following fault causes:
A. External leak on the VANOS system
B. VANOS oil pump
C. High pressure line (4)
If there is no external leak, check high pressure line for leak-tightness: Apply compressed air to the high pressure line (approx. 8 bar) (oil pan removed).
If the high pressure line has no leak: replace VANOS oil pump.
5. Connect a high pressure line to a cylinder head, (1) or (3)
6. Measure the VANOS oil pressure
- If the oil pressure is OK:
Internal leak in the VANOS system of the cylinder head that is not connected
- If the oil pressure is not OK:
Internal leak in the VANOS system of the cylinder head that is connected
Other troubleshooting if a leak was detected on a cylinder head:
- At the cylinder head concerned, remove the VANOS solenoid valves
- Check the O-rings of the VANOS solenoid valves
- If the O-rings are OK: replace the VANOS calibration unit of the cylinder head concerned
- If the O-rings are not OK: replace the solenoid valves concerned