What the B58 oil filter housing is and where to find it
The B58 is BMW's turbocharged 3.0-liter inline-six engine, found in models like the 340i, 440i, M340i, and M440i. The oil filter housing on this engine sits on top of the motor, toward the rear, and contains both the oil filter cartridge and the housing that holds it. Unlike older BMW engines where the filter screwed directly onto the block, the B58 uses a cartridge-style filter that slides into a plastic or metal canister.
The housing itself is a cylindrical component with a large cap on top. You remove the cap, pull out the old filter element, and install a new one. The housing also contains an internal bypass valve and a pressure relief valve, both of which can fail or stick over time. Because the housing sits high on the engine and connects to multiple oil passages, any leak or malfunction here affects oil pressure throughout the engine.
Key Takeaways
- The B58 oil filter housing is a cartridge-style canister located on top of the engine toward the rear, accessed by removing a large cap.
- The housing contains not just the filter but also internal valves that regulate oil pressure and bypass flow, so problems here can affect engine oil pressure readings.
- Removal requires draining the oil, unbolting the housing from the block, and replacing the rubber O-ring seal to prevent leaks on reinstallation.
- Common failure points include a stuck bypass valve (causing low oil pressure warnings), a cracked plastic housing (causing external leaks), and a worn O-ring that leaks oil around the cap.
- Replacement housings cost between $80 and $200 depending on whether you choose OEM or aftermarket, plus labor if you have a shop do the work.
How to locate and access the B58 oil filter housing
Start with the engine cold and the car on level ground. Open the hood and look toward the back of the engine bay, roughly in line with the firewall. The housing is a cylindrical component, typically black plastic on newer models, with a large hexagonal or round cap on top. On some B58 variants, a plastic engine cover or intake manifold may partially obscure it, so you may need to remove trim pieces first.
To access it fully, you will need to drain the oil into a pan below. The drain plug is on the bottom of the oil pan, toward the front-center of the engine. Once drained, the housing bolts to the engine block with typically two or three fasteners. These bolts are usually 10mm or 13mm and sit on the sides or bottom of the housing. The cap itself unscrews by hand or with a filter wrench if it is tight.
Removing and replacing the filter element
Once you have accessed the housing, unscrew the large cap on top by turning it counterclockwise. The old filter cartridge will come out with it or will remain in the housing. Pull it straight out and set it aside. Before installing the new filter, inspect the rubber O-ring seal that sits in a groove on the cap or inside the housing. If it looks cracked, hardened, or flattened, replace it with a new one—this is one of the most common sources of oil leaks after a filter change.
Slide the new filter cartridge into the housing, making sure it seats fully at the bottom. The filter should not be forced; it should slide in smoothly. Screw the cap back on by hand until the O-ring makes contact with the housing, then turn it an additional three-quarter turn. Do not over-tighten, as this can damage the O-ring or crack the plastic housing. Reinstall the housing bolts if you removed the entire housing, torque them to the manufacturer specification (usually around 25 Nm), and refill the oil to the correct level.
Common problems with the B58 oil filter housing
The most frequent issue is a stuck bypass valve inside the housing. This valve opens when oil is cold and thick, allowing unfiltered oil to bypass the filter element and reach the engine. If it sticks closed, oil pressure drops and the low oil pressure warning light comes on. This often happens after the engine sits for weeks or after a long period between oil changes. A bypass valve that is stuck open causes the same symptom because oil bypasses the filter constantly, reducing effective filtration.
A cracked plastic housing is the second common failure. The housing expands and contracts with temperature cycles, and the plastic can develop stress cracks over time, especially if the cap was over-tightened during a previous service. Cracks usually appear around the bolt holes or near the cap seat. A cracked housing will leak oil externally and must be replaced; it cannot be repaired.
The O-ring seal is the third frequent culprit. If it is not replaced during a filter change, or if it was installed incorrectly, it will harden and lose its seal over time. This causes a slow drip of oil around the cap, visible on the engine block below the housing. A new O-ring costs a few dollars and solves the problem when ready.
When to replace the entire housing versus just the filter
If you are only changing the oil and filter, you do not need to remove the housing at all—just unscrew the cap, swap the cartridge, and reinstall the cap. However, if you notice oil leaking from the housing itself, or if the bypass valve is stuck and you want to clean or replace it, you will need to unbolt the entire housing from the engine block.
Replacement is necessary if the housing is cracked, if the internal bypass valve cannot be freed, or if the bolt holes are stripped. A new OEM housing for the B58 typically costs $100 to $200, depending on your model year and whether you buy from a dealer or an online parts supplier. Aftermarket housings are usually $80 to $120. Labor to remove and install is typically one to two hours at an independent shop, or included in a full oil service at a dealer.
Oil filter housing maintenance and prevention
The best way to avoid problems is to change the oil and filter on schedule according to BMW's service intervals. For B58 engines, this is typically every 10,000 to 15,000 miles depending on driving conditions and the model year. Use the correct filter cartridge for your specific B58 variant—there are several part numbers, and using the wrong one can cause fit or bypass issues.
Always replace the O-ring seal during every filter change, even if the old one looks fine. The seal is inexpensive and is the easiest way to prevent leaks. When reinstalling the cap, tighten it firmly but not aggressively—hand-tight plus three-quarter turn is the standard. If you hear the engine knocking or see a low oil pressure warning light shortly after a filter change, stop driving when ready and check the housing for leaks or the bypass valve for sticking.
Frequently Asked Questions
What does it mean if the low oil pressure light comes on after an oil change?
This usually indicates a stuck bypass valve inside the housing or an O-ring that is not sealing properly. Check the oil level first to rule out underfilling. If the level is correct, the housing may need to be removed and the bypass valve cleaned or replaced. Do not ignore this warning, as low oil pressure can damage the engine quickly.
Can I replace just the O-ring without removing the housing?
Yes. The O-ring sits in a groove on the cap or inside the housing and can be accessed by unscrewing the cap. Pry out the old O-ring with a small tool, clean the groove, and press the new one in place. This takes about five minutes and costs a few dollars.
How do I know if my housing is cracked?
Look for a slow drip of oil on the engine block directly below the housing, or inspect the housing itself visually for visible cracks around the bolt holes or near the cap seat. A cracked housing will leak even if the O-ring is new and the cap is tight. It must be replaced.
What is the difference between OEM and aftermarket B58 filter housings?
OEM housings are made by BMW and are may provide to fit and function correctly. Aftermarket housings are made by third-party suppliers and are usually cheaper but may have slightly different internal valve specifications or durability. For a critical component like this, OEM is the safer choice if budget allows.
Do I need to reset anything after replacing the oil filter housing?
No. The housing itself does not require any electronic reset or coding. However, if the low oil pressure light was on before the replacement, it should turn off once the engine starts and oil pressure normalizes. If it stays on, there may be another issue with the oil pressure sensor or the engine itself.