BMW's MOST COMMON Oil Leak & How To Fix It! - Oil Filter Housing N54

Introduction

In this tutorial, we will guide you through diagnosing and fixing one of the most common oil leaks in BMW engines, specifically focusing on the N54 model but applicable to N20, N51, N52, and N55 as well. This process is crucial to prevent further damage to your vehicle, such as issues with the upper radiator hose, coolant flange hose, and serpentine belt.

Step 1: Gather Your Tools and Parts

Before starting, ensure you have all the necessary tools and parts ready. This preparation will make the process smoother and more efficient.

Tools Required

• 5K lb. car lift system
• 1/4" torque wrench
• 3/8" torque wrench
• Wobble E Torx sockets
• BMW oil filter cap tool
• Cooling system pressure tester
• Fluid extractor
• Inspection mirror set
• Sil-Glyde lubricant
• Red Scotch Brite pads

Parts Needed

• N54 oil filter housing reseal kit
• Aluminum coolant flange hose
• FUCHS oil service kit
• Zerex coolant

Step 2: Prepare the Vehicle

Follow these actions to prepare your BMW for the oil filter housing repair.

1. Lift the Vehicle: Use the car lift to elevate the vehicle safely. Ensure it is stable before proceeding.
2. Remove Engine Covers: If applicable, remove any engine covers that may obstruct access to the oil filter housing.

Step 3: Identify the Oil Leak

Diagnosing the leak is critical.

1. Inspect the Oil Filter Housing: Look for signs of oil pooling or dripping around the oil filter housing.
2. Check Surrounding Components: Examine the upper radiator hose and coolant flange for any signs of oil contamination.

Step 4: Replace the Oil Filter Housing Gasket

This is the main repair step to fix the oil leak.

1. Remove the Oil Filter: Use the BMW oil filter cap tool to unscrew and remove the oil filter.
2. Detach the Oil Filter Housing:
   • Use your Torx sockets to remove the bolts securing the oil filter housing.
   • Carefully pull the housing away.
3. Clean the Surface: Use red Scotch Brite pads to clean the mating surfaces of the engine and oil filter housing.
4. Install the New Gasket: Apply the new gasket from the reseal kit to the oil filter housing.
5. Reattach the Oil Filter Housing:
   • Position it back in place.
   • Secure with bolts and tighten using the torque wrench to the manufacturer's specifications.

Step 5: Replace the Coolant Flange Hose

If the coolant flange hose is damaged or contaminated with oil, replace it.

1. Locate the Coolant Flange Hose: Trace it from the engine to the radiator.
2. Remove the Old Hose: Detach it from both ends.
3. Install the New Hose: Fit the new aluminum coolant flange hose into place and secure.

Step 6: Refill Oil and Coolant

After completing the repairs, refill the necessary fluids.

1. Add Oil: Use the FUCHS oil service kit to refill the engine oil.
2. Add Coolant: Fill the cooling system with Zerex coolant.

Step 7: Test for Leaks

After reassembly, check for any leaks.

1. Run the Engine: Start the car and let it idle.
2. Inspect for Leaks: Look around the oil filter housing and coolant flange hose for any signs of oil or coolant leaks.

Conclusion

By following these steps, you should be able to successfully diagnose and fix the common oil leak associated with BMW's oil filter housing. Regular maintenance and prompt repairs can prevent further damage and ensure your vehicle runs smoothly. If you encounter any issues, consider consulting a professional mechanic for assistance.