BMW E46 330i (M54B30) engine oil leak - causes and solutions

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BMW E46 330i (M54B30) engine oil leak - causes and solutions

Common leak sources:

• Valve cover gasket
• Oil filter housing gasket
• Oil pan gasket
• Rear main seal
• VANOS seals

Diagnostic steps:

• Clean the engine thoroughly
• Run the engine and inspect for fresh oil leaks
• Use UV dye for hard-to-spot leaks

Solutions for common leaks:

• Valve cover gasket:
  - Remove valve cover
  - Replace gasket (BMW part number: 11127582245)
  - Torque bolts to 10 Nm
• Oil filter housing gasket:
  - Remove oil filter housing
  - Replace O-rings and gaskets (kit part number: 11421427782)
  - Torque bolts to 22 Nm
• Oil pan gasket:
  - Support engine
  - Remove front subframe
  - Replace gasket (part number: 11137513050)
  - Torque bolts to 12 Nm

Note: Always replace all accessible gaskets and seals during major repairs to prevent future leaks.