BMW 3 series crankcase vent valve replacement(E46)

Introduction

This tutorial provides a step-by-step guide on replacing the crankcase vent valve in a BMW E46 series, specifically a 2003 model. This process can help address issues like excessive oil consumption and improve engine performance.

Step 1: Gather Necessary Tools and Parts

Before you start, ensure you have all the required tools and parts:

• Tools:
  • T40 Torx screwdriver
  • 10mm socket
  • 13mm socket
  • Panel clip tool or screwdriver
  • Pick tool (90-degree)
• Parts:
  • New crankcase vent valve
  • Return line from the crankcase vent valve to the oil dipstick tube
  • Hoses connecting the vent valve to the valve cover and distribution block

Step 2: Remove Cowl Trim and Microfilter

1. Remove the cowl trim:
   • Locate the clips holding the trim in place.
   • Use a panel clip tool to carefully remove the clips.
2. Take out the microfilter:
   • Turn the twist locks on either side of the microfilter cover a half turn.
   • Pull the cover up to remove it.

Step 3: Remove the Air Box and Associated Components

1. Disconnect the air supply line:
   • Remove the vacuum line on top of the air intake boot.
2. Remove the air box:
   • Detach the front air intakes from the air box.
3. Take off the trim piece:
   • Remove the trim piece along the side of the brake booster.
   • If clips are missing, just pull gently.

Step 4: Remove the Variable Intake Valve

1. Disconnect the variable intake valve:
   • Locate the two T40 screws holding the valve.
   • Remove the screws, then disconnect the wiring harness.

Step 5: Remove the Throttle Body and Idle Air Control Valve

1. Detach the throttle body:
   • Unscrew the bolts holding the throttle body using a 10mm socket.
   • Disconnect the idle air control valve by removing its T40 screws.
2. Remove the dipstick tube:
   • Unscrew the 13mm bolt securing the dipstick tube to the engine mount bracket.

Step 6: Access the Crankcase Vent Valve

1. Locate the crankcase vent valve:
   • Identify the two screws (likely T25) holding the crankcase vent valve in place.
2. Remove the old crankcase vent valve:
   • Unscrew the bolts and carefully pull the valve out.

Step 7: Install the New Crankcase Vent Valve

1. Position the new crankcase vent valve:
   • Align the valve with the mounting holes.
   • Ensure to transfer any plugs from the old valve to the new one to avoid air leaks.
2. Secure the valve:
   • Tighten the screws to hold the new valve in place.

Step 8: Reattach Hoses and Components

1. Reconnect hoses:
   • Attach each hose to their respective locations, ensuring a snug fit.
   • Use a pick tool to help compress hose tabs if necessary.
2. Reassemble components:
   • Reinstall the throttle body, variable intake valve, air box, and any trim pieces you removed.

Step 9: Final Checks and Test

1. Check for leaks:
   • Start the engine and observe for any abnormal sounds or leaks.
2. Monitor oil consumption:
   • Keep an eye on oil levels after the replacement to ensure the issue is resolved.

Conclusion

Replacing the crankcase vent valve on your BMW E46 can significantly help with oil consumption issues and improve engine efficiency. Always remember to work carefully and methodically, ensuring all connections are secure. If you encounter difficulties, consulting a professional mechanic is advisable.