N52 compression test must be performed with the eccentric shaft angle being at 176°. It can be set using ISTA+ scantool or manually using an allen key on the eccentric shaft actuator motor. A scan tool like ISTA+, BimmerLink, DeepOBD or Protool must be used to monitor the eccentric shaft position while turning

Healthy Values must be between 180 psi and 210 psi. With a maximum gap/variation of 29 psi between the highest value and lowest value.

150 psi is the minimum allowed before the engine requires a rebuild

Note: Depending on the position of the eccentric shaft, compression range can vary from 130 psi up to 265 psi

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Cases implying a compression test:

• Unexplained cylinder misfires
• Excessive Oil burning (Spark plugs fouled with oil)
• Unexplained Rough automatic transmission shifting and torque converter mishifting (Lockup/regulation) behaviour
• Long cranking
• Low power delivery at low engine speeds
• Mild engine vibrations/oscillations at idle
• Unexplained lean Air/Fuel mixture condition