Are Genuine BMW Parts Better? October 09 2018

My friend insists on using only genuine Mercedes Benz oil filters, spark plugs, fluids and pretty much everything else. Genuine parts and fluids from the manufacturer are usually more expensive, but my friend is willing to pay more to ensure the quality of the parts. Is this a situation where you get what you pay for?

Mahle oil filter next to a Genuine BMW oil filter.

The answer is: sometimes. Take these BMW engine oil filters for example. Based on my experience in the engineering profession and my time spent repairing, maintaining and modifying cars, I would wager that genuine BMW oil filters aren't actually made in a factory owned by BMW. I have compelling evidence to suggest that BMW contracts out oil filter production to Mahle. BMW likely establishes some specifications for the oil filter and then has Mahle crank them out. After all, Mahle specializes in making oil filters for many different cars and has the economies of scale to make them for less money than BMW could. Compare these two filters side by side. The filter on the left is from Mahle and the filter on the right is a genuine BMW part.

Side by side comparison of Mahle and Genuine BMW oil filters. Both have a marking that reads "OX 187".

The parts look identical to each other, with the exception of branding and part markings. But look at the part numbers. They both even have the Mahle part number stamped on them (OX 187). They're also both made in Austria. So are you getting a better part when you pay extra for the genuine BMW oil filter over the Mahle one? I haven't run tests on the filters, but my educated guess would be no.

In today's manufacturing landscape, it makes sense for automakers to subcontract other companies to make certain parts. The subcontracted companies are referred to as original equipment manufacturers, or OEMs. OEM parts will typically be made in the same factory as the genuine parts are, and will almost invariably have the same quality as the genuine parts. If Mahle makes oil filters for BMW, and then goes on to make oil filters under their own brand, why would Mahle spend the time and effort to retool their production line to produce oil filters to different specifications? Baring contractual obligations, it doesn't make sense to do so, and this is further reason to believe that Mahle and genuine BMW oil filters are the same.

So how do you know who is an OEM for BMW? You may have to do some research, or you may have to look for OEM markings on the part. Sometimes your parts supplier can provide information about the manufacturer and whether they are an OEM to BMW. Bosch, Mahle, Behr, Ate, Girling, Brembo, Castrol, ZKW, Getrag and BBS are some common BMW OEMs. 

So does it ever make sense to buy genuine BMW parts? One example is when there is no readily available OEM equivalent to the genuine part. I use genuine BMW coolant, because the formulation is exclusively manufactured for BMW and I haven't been able to find coolant directly from the OEM. This coolant has a specification of having no phosphates, no nitrates and low silicate content. There are discussions on the internet talking about suitable substitutes to genuine BMW coolant, but I haven't found any definitive answers. I find the reduced risk to the coolant system and engine enough to justify the added cost of buying genuine BMW coolant.

BMW coolant jug with "exclusively formulated for BMW" highlighted.
Back of BMW coolant jug that says no phosphates are in the formulation.

Other examples of when it makes sense to buy genuine parts would be buying body panels, interior trim pieces and exterior trim pieces. These parts are built with access to the original engineering drawings, so fitment is usually slightly better than a part that is reverse engineered.

Below is a list of items that I personally don't think make sense to buy as genuine BMW parts:

Engine oil, oil filters, transmission fluid, final drive fluid, spark plugs, brake pads, brake rotors, brake fluid, windshield wiper blades, fuses, light bulbs, batteries, alternators.

That being said, you also need to do some research to verify that the part you're buying instead of the genuine part is made by the OEM or that it meets or exceeds the factory specifications. Otherwise, you're not saving money by buying an equivalent product, but rather paying less for an inferior product. For example, skipping the fully synthetic genuine BMW 10W-30 motor oil and buying a conventional 5W-20 instead doesn't make sense.

Let me know in the comments if I've missed a part that doesn't make sense to buy as a genuine BMW part.