FAULTBASE
Error CodesASKCars
© 2026 FAULTBASE
All rights reserved.
v2.0.0 • Production
ContactPrivacyImpressum
why does my BMW 3 Series E90/E91 (2005-2012) have a weird exhaust smell - BMW 3 Series
Home/Cars/BMW/3 Series/E90/E91 (2005-2012)/why does my BMW 3 Series E90/E91 (2005-2012) have a weird exhaust smell

why does my BMW 3 Series E90/E91 (2005-2012) have a weird exhaust smell

BMW 3 Series E90/E91 (2005-2012)

Error Codes
2-4 hours
Time
medium
Difficulty
medium
Severity
Navigation
ProblemSymptomsDiagnosisSolution
ProblemSymptomsDiagnosisSolution
3 min read
510 words

Problem Statement

The BMW 3 Series E90/E91 (2005-2012) is experiencing a strange exhaust smell, which may indicate an underlying issue with the engine or exhaust system.

Estimated Time
2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

  • •Disconnect the battery before working on electrical systems.
  • •Allow the engine to cool before inspecting the exhaust system to prevent burns.

Symptoms

  • •Unusual or strong exhaust odor, potentially sweet or sulfuric
  • •Check engine light illuminated
  • •Decreased fuel efficiency
  • •Engine misfires or rough idle
  • •Increased emissions from the exhaust

Diagnostic Steps

  1. 1
  2. 2
  3. 3
  4. 4
  5. 5

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

After completing the repair, verify that the issue has been resolved:

  • ✓Test the affected component to ensure it functions correctly
  • ✓Check for any error codes or warning lights
  • ✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

  • •Follow the manufacturer's recommended maintenance schedule
  • •Address warning signs early before they develop into major issues
  • •Use quality parts and fluids recommended for your vehicle
  • •Keep detailed records of all repairs and maintenance

Tools & Equipment Required

  • •OBD-II scanner
  • •Socket set
  • •Torque wrench
  • •Screwdrivers
  • •Pliers

Parts Required

  • •Catalytic converter (if faulty)
  • •Head gasket (if needed)
  • •Exhaust clamps and gaskets (if damaged)

Additional Information

Estimated Time
2-4 hours
Difficulty
medium
Severity
medium
Tools Required
5 items
Parts Required
3 items

Related Faults

Loading...

Share this solution

Comments

Sign in to share your thoughts

Sign In

No comments yet

Be the first to share your thoughts

Back to Generation
Solution
1. Preparation
  • Gather necessary tools and parts.
  • Ensure the vehicle is parked on a flat surface and the engine is cool.
  • Disconnect the battery to prevent any electrical issues during repair.
2. Inspect and Repair Exhaust Components

  • Inspect Exhaust System:

    • Visually check for cracks, leaks, or loose connections in the exhaust pipes, muffler, and catalytic converter.
    • Tighten any loose clamps or connections as needed.

  • Replace Catalytic Converter (if faulty):

    • Remove the bolts securing the catalytic converter to the exhaust system using a socket set.
    • Disconnect any oxygen sensors attached to the catalytic converter.
    • Install the new catalytic converter, ensuring proper alignment and sealing.
    • Torque the bolts to the manufacturer's specifications (typically around 30-40 Nm).
3. Address Engine Issues

  • Check for Coolant Leaks:

    • Inspect hoses for leaks and check the water pump and radiator for any signs of coolant loss.
    • Replace any damaged hoses or components.

  • Replace Head Gasket (if necessary):

    • If coolant contamination in oil is confirmed, remove the intake manifold and cylinder head.
    • Clean surfaces and install a new head gasket, ensuring proper torque specifications are followed (typically 30 Nm, then 90 degrees).
    • Reassemble components and refill coolant.