Sorry, didn't mean to offend. I should use more smileys.

But you did say that anything that goes through the filter can't hurt the engine. That is true for oil filters, which filter continuously recirculating oil. It isn't true for air filters, which get one pass. It is the quantity of what goes through the filter that harms the engine. You will see it in regular oil sampling results.

Side note. Not BMWs, or even gasoline engines, but filters none the less. My toughest filter challenges were all in dry climates, probably not unlike Texas. The shots below were taken at a customer site. We had the filter contract, as well as the new machine warranties and the fleet availability guarantees. We did a lot of studies and measuring, it was how we kept the fleet running. Notice the paper mask the driver is wearing in the first shot. He knows what is coming. The second shot was spotting the truck under the bucket, the third was as the loader operator dumped the bucket of the 992. Three or four passes, then repeat. They did this all day.

Attached Images

   

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue