my BMW 3 Series E90/E91 (2005-2012) has a burning smell coming from engine what to check

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety while working on electrical components.
• Allow the engine to cool before beginning any inspections.

2. Inspect and Address Fluid Levels

• Engine Oil:

  • Remove the oil dipstick and check the oil level.
  • If the oil appears burnt or low, drain the old oil and replace it with new oil of the manufacturer’s recommended grade.
  • Replace the oil filter if necessary.

• Coolant:

  • Check the coolant reservoir and top up with a 50/50 mix of coolant and water if low.
  • Inspect hoses and connections for leaks; replace any damaged hoses.

3. Inspect Electrical Components

• Visually examine the wiring harness and connectors around the engine for signs of melting or burning.
• If damage is found, carefully repair or replace the affected wiring or connectors.
• Ensure that all connections are secure and insulated properly.

4. Check for Leaks

• Inspect the engine oil pan, transmission, and any seals for leaks.
• Tighten any loose bolts or replace gaskets if necessary to stop leaks.
• Clean up any spilled fluids to prevent further burning smells.

5. Reassemble and Test

• Reconnect the battery and ensure all components are properly secured.
• Start the engine and observe for any abnormal smells or smoke.
• Monitor fluid levels again after the engine has run for a short period.