i was wondering why large amounts of water was getting in the passenger compartment of my 01 Monte everytime it rained or when i washed my car at first i thought it was the heater core but i checked that, the heater core checked out to be fine so something told me to check my cabin air filter and guess what???????? the previous owner took it out and never replaced it some ppl do the dumbest thingz, im just glad i caught it in time b4 it damaged anything electrical,carpet etc i had large amounts of water on the of the carpet and under the carpet but the car is ok now becuz it rained like hell all day 2day

 

LOL same thing happened to me on my 00 ls. Scared my s-less when I got in. I though everything would be ruined. But good thing you did catch it early!

 

First off you don't necessarily need a cabin air filter because 97-03 Grand Prix's don't come with them, and Grand Prix's and Monte's are basically the same car just look different on the outside. Secondly i doubt very seriously that you not having a cabin air filter was the reason it was leaking. Think about it, it filters the air. It has nothing to do with stopping water. I GURANTEE you it'll leak again.

 

It's the rubber weather stripping around the passenger side cowl when you take it off that deflects the water. Not the actual filter.

If you want to STOP the water completely, go to a dealer and order part #: 15794785

There is a little modification to the cowl that you have to do to make it fit, but water will NEVER get into the cabin air filter area again. (it's the part the 7th Gens have, I was able to get it on my car) Should be about $3