Greetings,

I just replaced the cabin filter on my '04 XC90. I bought the 1.5 inch replacement. When I took the cover off, I found two filters, the 1.5 inch one and a 1 inch filter rearward of the 1.5 " one. I replaced the 1.5 inch filter, and, because I did not know to buy a 1" replacement, I stuck the 1" filter back in (even though it needs replacement), as I did not want to leave part of the compartment empty. So, what's the story, I wonder? Are both filters necessary? Will one do? Should I remove the old 1" one and replace it, or am I good with just the 1.5"?
Thanks

There are 2 types of filtration systems. Yours has a carbon filter, I believe. While it is a pain, I would get the 1 inch filter and replace it. Did you vacuum the old filter before putting it back in? That one catches leaves and other large particles.
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Keeping it running is better than buying new

if I recall correctly it was one or the other, depending whether the cars has IAQS.

While I could be mistaken, I'd imagine the 1.5 inch alone is well suited for the job. 2.5 inches of filtration media could possibly reduce airflow??

That said, I only ran the 1.5inch in my previous P2 S60.

Steve

Thanks you both!