I read the warnings too late. I had a K&N air filter in my Disco for about 4000 miles and this is the result:


It doesn't seal correctly, because the gasket on the filter is much thinner than on paper filters like the ones from Mahle. I had never such problems with a Mahle filter. I always make sure, that the box is tightly closed and latched properly. As can be seen on the picture, the dust bypassed the filter.


The MAF is covered in dust. The darker spot is from wiping with my finger over the screen. It was very dusty inside on the elements too. I had to buy MAF cleaner and clean the MAF. Luckily I didn't get any MAF related codes before and after.

Lesson learned.