I posted this question over in Maintenance, but I'm hoping it'll get more attention here. Does anyone happen to know whether the pollen filter is upstream or downstream of the AC evaporator? If the former, it's probably helping to keep the evaporator from getting clogged, and so I'll leave my filter in. If the latter, I might try running with the filter out, as you get much more air our of your dash vents without it, and the air does seem a bit fresher (I tried it for a few miles last night). Can anyone think of other problems that running without the filter might cause, I mean besides the obvious sneezing at pollen, etc.? Thanks.

 

Small leaves and debris could get trapped in the blower blades and cause noise.

My Civic doesn't have a filter and I occasionally have to dismantle the blower to clean it out.

 

Most cars that DON'T have a cabin air filter usually have a fine mesh screen over the intake to filter out leaves and insects. I don't think the fit has this, as I've looked at my pollen filter and noticed several fair size bugs trapped in it already. I'd hate to have the fresh air system inhale a hornet.

Since I'm a life-long hay fever sufferer, the filter stays in. Also, the interior of your car will stay much cleaner with the filter in place.

 

Never seen one that wasn't designed prior to the AC evaporator core.

The bugs the previous post found would also tend to re-enforce this otherwise the bugs should be caught by the AC first......

 

Thanks for the advice. I'm now wondering about some sort of compromise. I might cut a piece of window screen to size and set it into the filter tray. As the airflow is downwards, this would catch the bugs and leaves and hold them, but add only slight resistance. I had the car out again last night without the filter and the airflow through the cabin with the fan set at 2 is noticeably better, and I think the AC works more efficiently this way as well.