Replacing Cabin Air Filter
 

I just bought an STP cabin a/c filter for my 2008 350es. The directions on the filter says to install it so the arrows are pointing in the direction of the air flow. I don't know what direction it flows. One thread I read said down but I would like to verify that before installing. I could leave the filter out and put my hand in it's cavity with the a/c on to find out but I don't know if or how the car's computer would react to that.

Does anyone know for sure which way the air flows and if so, could you tell me how you know?

By the way, the filter cost me $15.00 at Auto Zone in Houston. It has no charcoal so it's no good for smokers or pet lovers but otherwise it's fine.

Thanks

As I recall, the air flows downwards. The reason I'm thinking this is that all the dust and debris collects on the topside of the filter, which means that is where the fresh outside air enters the filter.

Thanks, Elex. That makes sense. My original filter had no arrows or position instructions and I couldn't remember for sure what side was up when I took it out.