Like the previous generation of 3-series BMW, the N-series engines in the E90 chassis are notorious for oil filter housing leaks. This gasket is critical to a healthy engine as it prevents oil from getting out of the engine, along with keeping the oil out of the cooling system. The oil that the gasket contains is under high pressure and will quickly escalate the leak's severity once its forms.
Watch below as Gareth Foley tackles this job on a BMW 328xi. During the video, you can see him take care of the oil pressure switch and the coolant flange while the oil filter housing is out of the way. Replacing both of those parts is cheap and a great way to future-proof any possible maintenance.
BMW models and years applicable:
Symptoms of a leaking BMW E90 oil filter housing gasket:
- Oil leak around the front of the engine
The oil filter housing is a common leak point on this series of BMW engines. The old gasket dries up and shrinks, allowing oil to weep past. An oil leak from the oil filter housing is a high-pressure oil leak that will negatively affect your engine's performance. If you have detected this oil leak, repair it as soon as you can.
Just below the oil filter housing is the cylinder head's coolant flange. It is made of plastic and is notorious for cracking with age. Oil residue on the plastic will increase its deterioration and potentially cause a leak that'll leave you stranded on the road. Included in the parts list is an aluminum flange that will take care of any cracking issues going forward.
A little further below the coolant flange is the engine's drive belt system. Oil residue on the belt will cause the rubber belt to swell and deteriorate. If you notice that oil residue has made it to the belt, it may be a good idea to change that out as well.
How much will it cost to replace the oil filter housing gasket on a E90 BMW?
The oil filter housing gasket kit will run you $25.94. The kit includes the new gasket, the housing's three new mounting bolts, and a new oil pressure switch. Along with that kit, the oil change kit you need is $64.97. Those two will cover everything you need for this job.
However, we recommend that you spend another $17.92 on the aluminum coolant flange. The OEM flange is plastic and is a common failure point in the cooling system.
How long will it take to replace the oil filter housing gasket on a E90 BMW?
With the right tools and parts, the job shouldn't take more than a few hours. Those of us with lots of wrenching experience can have it done sooner. Both coolant and engine oil need to be drained and replaced during the job. Taking your time is critical to completing the job yourself.
Parts required to replace the oil filter housing gasket on a E90 BMW:
Tools required to replace the oil filter housing gasket on a E90 BMW:
- E10 Socket
- T20 Bit Socket
- T25 Bit Socket
- 10mm Socket
- 24mm Socket
- Oil Filter Cap Socket - CTA 2489
- Ratchet Extensions
- Torque Wrench
- Flathead Screwdriver
Steps required to replace the oil filter housing gasket on a E90 BMW:
Step 1: Drain the fluids
Jack up the car and place a drain pan underneath the oil pan drain plug. Then, use a 17mm socket to remove the drain plug.
Refit the drain plug with a new crush washer to the oil pan after the oil has stopped draining. Next, head into the engine bay and use the CTA oil filter socket to remove the housing's oil filter cap.
Place some rags into the oil filter housing to soak up as much of the oil inside it as you can to cut down on the amount of oil that runs out of the housing when you remove it.
Next, loosen the cap on the coolant expansion tank to open up the cooling system. Then, head under the car and locate the radiator drain plug at the bottom of the radiator. Place a drain pan under the radiator and use a quarter and pliers to remove the drain plug.
Refit the drain plug back into the radiator after the coolant has finished draining.
Step 2: Remove the oil filter housing
First, you need to remove the upper radiator hose from the filter housing. Unlock the hose with a pick and then pull the hose off of the housing.
Next, remove the housing's three mounting bolts. One of the bolts is tucked behind the housing, below the intake manifold. Use a swivel E10 socket on a long extension to reach the rear bolt.
Next, remove the top mounting bolt.
The housing's final mounting bolt sits behind the coolant flange on the front of the engine. To get this bolt out, you have two options. You can use an E10 ratcheting box-wrench and sneak the bolt out as you pull the housing off, or you can unbolt the coolant flange. Removing the flange allows you to install the aluminum flange and replace the cooling system's common failure point.
If you opt to remove the coolant flange, use a 10mm socket to remove the two bolts that mount the flange to the engine—wiggle the flange around to break the o-rings seal and remove it from the cylinder head. For extra room, disconnect the coolant temp sensor.
Lastly, remove the final mounting bolt and then pull the housing off of the engine.
Step 3: Clean the housing and replace the gasket
Use brake clean and rags to remove the oil residue and dirt build-up from the outside of the housing. Then, use the same cleaning supplies to clean off the engine. Removing the dirt and oil will prevent debris from interfering with the new gasket and causing a leak.
Now is the best time to replace the oil pressure switch as it's very difficult to remove with the hosing on the engine.
Use a 24mm wrench to remove the old switch and tighten the new one.
Next, flip the housing over and remove the old gasket with a pick. Ensure that none of the old gasket remains in the housing, as it will interfere with the new gasket and cause a leak. Then, press the new gasket into the housing.
Step 4: Reinstall the housing and coolant flange
Unfortunately, you need to cut off the clamp BMW used to hold the coolant hose to the coolant flange to replace the flange. If you install the aluminum coolant flange, use diagonal cutters or a Dremel-tool to cut the clamp off the hose.
Next, refit the oil filter housing to the engine—thread in the front and upper bolt before threading in the rear. Use an E10 swivel socket to tighten and torque all of the bolts to 22Nm. Then, reconnect the oil pressure switch and the coolant temp sensor.
After that, fit the coolant flange into the cylinder head and secure it with its two 10mm bolts. Then, fit the coolant hose over the flange and secure it with a standard hose clamp. Torque the bolts to 10Nm.
Lastly, reconnect the upper radiator hose to the filter housing. Check the o-ring inside of the hose before fighting it to the housing and replace it if it is dry and flat. Push in the lock tab to secure the hose to the filter housing.
Step 5: Replace the oil filter and fill the vehicle with fluids
Remove the old filter from the housing cap., then use brake clean and rags to clean the cap. Next, use a pick to remove the old o-ring from the cap and replace it with the new one supplied in the kit. Then, press the new filter into the cap.
Dab some fresh oil on the cap's o-ring to prevent binding, and thread the cap into the housing. Thread the cap in by hand before using the CTA socket to torque it to 25Nm.
After that, fill the engine with all seven liters of oil included in the oil change kit.
Then, fill the cooling system with about a liter, each, of distilled water and BMW coolant. This amount will vary so get as close to a 50/50 mix as you can until the coolant expansion tank reads full.
BMW E90 Oil Filter Housing Torque Specs:
- BMW Oil Filter Housing Bolts = 22Nm or 16.2 ft-lbs of torque
- BMW Coolant Flange Bolts = 10Nm or 7.4 ft-lbs of torque
- BMW Oil Filter Housing Cap = 25Nm or 18.4 ft-lbs of torque