RickM5X3. You have a handy thing in your signature, mentioning your cars (year, type, platform) which all should do - as it helps to target vehicle specific advice. Your old and new cars don't show platform (2008 would be E70, 2005 would be E53 in Europe).

Are you asking about microfilters for an E53 or E70 X5?

For the E53, you will see that the filter has an arrow to indicate direction of flow. BMW unfortunately doesn't put an arrow on the housing or access flap (when you change the filter) to guide you, nor is it indicated in the factory service manual. Direction of flow is from the bottom to top, so the arrow points UP.

For the E70, are you speaking of the twin filters (under the hood)? If yes - they can only be snapped in place in one direction. If your E70 also has the third filter just behind the glove box, (accessed from inside the car) you'll see how it comes out (I can't recall off the top of my head).

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2002 Euro X5 (E53) 3.0 diesel (M57)
5 speed manual with UUC short shifter.
Pre-xDrive NV125 transfer case (chain & gears).
Factory Xenon headlights, Spyder LED tail lights
Updated vortex crankcase breather.
Motorsport dead pedal, factory fire extinguisher, factory first aid kit, factory F&R mud flaps, factory PDC

Bilstein B6 shocks F&R
Redline oil has replaced "lifetime" fluids (F&R diff, manual transmission, transfer case and P/S).
Dimple magnetic drain plugs in all compartments.