BMW Oil Filler Cap Leak - E90

The seal in the BMW oil filler cap will begin to harden and deteriorate which allows oil to leak. Judging by the amount of posts I see in BMW forums, this seems to be a very common issue.

To stop the leaking:

1. Buy and replace the oil filler cap. The new cap comes with a seal. 
• Part # 11128507153 for E9X BMWs with the round oil filler cap. Earlier E90, E60, E85, and late model E46s use this square oil filler cap.
• Part # 11127509328 for earlier model BMWs with the square oil filler cap.  
2. Carefully remove the existing seal. Clean and reinstall by reversing the ring. I would only try this if the leak is very small and I don't want to spend $15.

My leaking oil filler cap:  

I changed my oil and the oil level read max in iDrive. A couple of weeks later, the oil level dropped and it didn't seem right that I would lose oil that quickly.

I noticed dried oil around the oil filler cap and oil leaking down onto the valve cover area. I pulled my oil cap and it looked like mustard. After doing some research and asking some friends, I came to the conclusion that my oil filler seal was bad and condensation was coming in and mixing with the oil and looking like mustard on the cap. I replaced the oil filler cap and oil consumption is now normal and no more weird mustard looking oil under the cap.

Below is what my old oil cap looks like and the seal that is indented. There is caked oil all around.

N55 HPFP Failure

Can the HPFP fail on a N55?

• Yes, my HPFP failed at 38,000 miles. 

What were the symptoms? 

• Very long cranks, rough idle, engine would randomly surge between 600 - 1800 rpm at idle and low speeds. The latter is particularly scary when pulling into or out of tight parking spots and the car would lurch. 

What did I do?

• I believed failing HPFP were confined to the N54 and were resolved with the N55, I was wrong. I brought my car into the dealer and they diagnosed my HPFP was failing and replaced it. My car issues went away with the new HPFP.

Why am I posting this? 

• Every once in a while I will see a post on the internet asking if the N55 fixed all the HPFP issues. I would say probably with the newer BMWs. Model years built right after N54 may still have the faulty HPFPs. 
• If you are looking to buy a used early model N55, the HPFP has a warranty of 10 years/120,000 miles and yes it can prematurely fail on you.  

How to Change Engine Oil on a BMW 3 Series E90

Tutorial for replacing engine oil & filter on BMW 3 Series E9X (06-12) with N51, N52, N54, N55 engines.

Tools:

• 17 mm socket and ratchet
• Lisle Oil Drain Pan
• Assenmacher Oil Filter Housing Wrench
• 21 mm socket and ratchet if using Assenmacher oil filter wrench
• RhinoRamps (Pair, 12,000lb. GVW Capacity)  

Parts:  

• Mann Oil Filter (Comes with drain plug and two O-ring gaskets) 
• Synthetic motor oil, options below:
• Genuine BMW 5W-30. Part number 83212365946
• Mike Miller from Roundel Magazine uses Red Line 0W40 Motor Oil - 12 Quarts 
• 2 x Castrol EDGE 0W-40 - 5 Quart European formula
• 2 x Mobil 1 Synthetic Motor Oil 0W-40, 5 Quart 
• Shell PurePlus synthetic oils

Recommended:  

• Rags, shop towels, jack and jack stands if you don't have ramps.
• I use Scott Shop Towels Pack of 2.
• Camco Wheel Chock - Pack of 2. If you jacking the front or using ramps, chock rear wheels to prevent your BMW from sliding. 
• Flat head screwdriver or General Tools Scriber
• Lumax Plastic Funnel

Steps:

• If engine is cool, start your car for 5-10 minutes to warm oil. If engine is hot, wait around 30 minutes to prevent being burned.  

• Lift BMW with a jack and jack stands or drive onto ramps. 
• Driving onto ramps is preferable if equipped with sports suspension and/or aerodynamic package due to low clearance.
• Jack one side and place jack stand or a ramp. Repeat on other side if  front bumper will be damaged driving up ramp or low profile jack cannot access the front jacking point. 
• Use a BMW Jack Pad Adapter to prevent destroying plastic side jack points.  

• Open hood and remove oil filter using Assenmacher Oil Filter Housing Wrench.
• The oil filter cap is shown below and the oil filter wrench goes on top. Place a 21 mm socket where the red circle is and loosen filter cap. 
• Place rags or shop towels around the oil filter to minimize spills when pulling out filter. 

• Locate oil drain plug access door. Door is located behind the front jacking point on RWD models and behind the transfer case beef up plate as shown below. Use a flat head screw drive and turn screw counter-clockwise to unlock shown in red circle below.

• Place an oil drain pan beneath door.

• Use a 17 mm socket and remove oil drain plug. Around 7 quarts (6.5 liters) of oil will drain out. 
• Drain plug is highlighted in red below. 
• I suggest wearing gloves to protect your hands.

• Remove and replace oil filter and two rubber O-rings while oil is draining. 

• Remove old filter from cap by pulling.
• I use a scribe to remove the old O-rings. Be careful not to damage the oil filter cap, especially the threads.
• Install new oil filter and two O-rings. Refer to the picture below from the Bentley BMW 3 Series Service Manual.
• Coat sealing O-rings with new oil
• Place large O-ring in correct location. Do not place in gap between cover and threads, place it in the correct gap below.

• Install new filter into oil filter housing and torque to 18 ft-lbs.

• Remove and replace copper washer on drain plug.

• Reinstall drain plug using 17 mm socket and torque to 18 ft-lbs. Do not over tighten. 

• Close access door and lock with screwdriver.

• Remove drain pan and lower BMW. 

• Remove oil fill cap and refill crankcase with 7 Quarts (6.5 liters) of oil.
• I pour 1 quart of oil into oil filter housing and 6 quarts into the engine. 
• Oil fill cap may be round or square depending on year and engine. N55 is pictured below.

• Reinstall oil fill cap and start engine. Check for any oil leaks and confirm the oil warning light is not on or goes out. 

• Check oil level in iDrive or the information center on the dash. Two conditions must be met to show oil level:
• Oil must reach normal operating temperatures 
• Start engine and idle or drive around for at least 6 minutes

Notes:

• Dear BMW, bring back the oil dipstick.
• Wipe away old oil in the oil filter housing after removing the filter.
• Many enthusiasts like Mobil 1, Castrol Edge European formula, or Shell PurePlus 0w-40 synthetic oils. As long as BMW's oil requirements are met you will be fine. Please refer to the owner's manual. 
• I recommend using wheel chocks for safety. 
• Picture below has useful information from Bentley's BMW 3 Series Service Manual   
• To reset CBS go to CBS explained