Case Studies

Why An Oil Filter Housing Leak On A BMW Engine Shouldn’t Be Ignored

What Happens
Oil leaks on any engine are both a nuisance and fact of life but few can cause damage like the BMW oil filter housing gasket.
I haven’t seen too many higher mileage BMWs that don’t have some kind of oil leak that goes without repair. The N 54 and series of engines have been excellent, and very durable, once the oil leaks are handled. However, they are not engines that do well when the oil leaks are not promptly and professionally addressed.

If there’s one oil leak on these engines that is critical to address, it’s the oil filter housing gasket. This rubber gasket seals the oil filter housing to the cylinder head and is one of the most common sources of oil leaks on most BMW engines where the oil filter housing bolts to the engine block or cylinder head. Now, why is oil filter housing gasket leak this serious of an issue on these engines? Simply put, it can lead to severe engine damage or even failure. Yes, you read that correctly, and no, I’m not exaggerating; it can, in fact, lead to engine failure and you’ll see from the photos an engine that met its demise. Again, I want to reiterate that this is from what started as an oil filter housing leak.

In the photo, you’ll note shards of serpentine belt material that are inside of the engine. How does serpentine belt material end up inside an engine? It’s due to the design of the harmonic balancer/crank pulley assembly on these engines and the position of the serpentine belt relative to the engine block. The oil filter housing leak, when severe enough, can create a trail of oil all the way down the front of the timing cover, eventually coating the serpentine belt and crankshaft pulley. Once the oil is on the serpentine belt and the crank pulley portion of the harmonic balancer, it’s almost inevitable that the serpentine belt will begin to degrade and come off the tensioner pulley. Since the harmonic balancer is in front of the crank pulley, the serpentine belt has nowhere to go but back towards the timing cover if it slips off. Once it slips off the crank pulley, it shreds the belt and forces the pieces through the front crank seal.

Unfortunately, the BMW engine in the photos above suffered this failure. It appears that a new front crank seal was installed and the oil leak was repaired. However, whoever made the repair didn’t bother to inspect as to whether the serpentine belt was sucked inside the engine (they probably thought it was flung off). This engine had severe rod knock, and once it was opened up it became pretty clear what went wrong. The amount of debris in the oil pick-up tube likely created an oil starvation issue which eventually led to rod bearing failure. There, more likely than not is another damage in this engine based on the amount of debris found inside of it.

Save Your Car
The takeaway here is that it’s important not to overlook an oil filter housing leak on these BMW engines. If there’s a small leak I’m not telling you to pull over and get the vehicle towed; what I’m saying is what starts off as a small leak almost always gets worse. In the case of N5X engines, a severe oil filter housing leak that can be repaired with a relatively inexpensive gasket can end up costing you thousands of dollars later on or worse, a complete engine replacement.

How We Can Help You
The Service Team here at Atlantic Motorcar is well experienced in this issue, and others, with over 35 years of Volvo specialization, serving clients from the areas of New England, we are familiar with the needs of the special service of your Volvo. Since we have diagnosed and treated this problem many times, we have the experience and qualifications necessary to return your Volvo to its original self.

As Maine’s leading European auto specialists, we provide expert-quality services at a fair rate than nearby dealerships and specialty shops. If you’re experiencing any of the above-mentioned symptoms in your own Volvo, please call us right away, we can usually see your car the same day! At Atlantic Motorcar we’ve developed some very specific procedures and tooling, combined with our expert technicians, to make this otherwise onerous repair a snap.

Questions, or if we can be of help in any way with service on your Audi, BMW, Mercedes, Mini Cooper or other European (and now Japanese) import, please contact us. Our team of Service Specialists is here to help, for even the newest autos! (207) 882-9969.

Knowing, not just “doing”, that’s the Atlantic Motorcar Center way of life.

The Atlantic Motorcar Center Service Team