Lainey said the van smelled like "a wet basement," and she wasn't wrong. When I pulled the cabin air filter out from behind the Sienna's glove box on Sunday, there were leaves in it, a maple seed and what I'm fairly sure used to be part of a bird's nest. The filter had gone from white to the color of a paper grocery bag.
I checked the notebook and found that the last time I wrote down a cabin filter for the van was 2021. The engine air filter wasn't much better. The Silverado's engine filter had been in since the spring of 2023. Both vehicles were overdue, and it was my fault, because filters are easy to forget when nothing is making a noise.
What it cost and what a shop charges
For the van, a cabin air filter was $14 and an engine air filter was $17 at the local parts store, so $31 for the pair. The truck's engine filter was another $19. That was the whole bill.
A quick-lube place will usually offer to replace these during an oil change. The last time someone did, the counter guy held up our dirty filter and quoted $64 for the cabin filter and $49 for the engine filter, installed. I'm not saying a filter isn't worth replacing. I'm saying the van's took me less time than the conversation did.
Where they hide on the Sienna
The cabin filter on a 2011 Sienna lives behind the glove box. Here's how ours went:
- Empty the glove box. Ours had three ice scrapers, two of which were from previous winters and none of which we could find in January.
- Unhook the little damper arm on the right side of the glove box.
- Squeeze the sides of the glove box inward so the stops clear the dash, and let it swing down.
- Unclip the cover on the filter housing, slide the old filter out, and note the airflow arrow printed on its edge.
- Slide the new one in with the arrow pointing the same way. On ours it points down.
Hold a trash bag under it when you pull the old one, because whatever is living on top of it will fall onto the floor mat. I vacuumed out the housing opening while it was open, which got the maple seeds that had fallen past the filter.
The engine air filter is in the black plastic box on the driver's side of the engine bay. A few metal clips hold the lid down. Pop them, lift the lid, pull the old filter, wipe out the bottom of the box with a rag, and drop in the new one with the rubber edge seated all the way around. If the lid doesn't close easily, the filter isn't seated, and you shouldn't force it. An engine air filter that isn't sealed lets dirt bypass it entirely, which defeats the point.
Both filters on the van, start to finish, took me 15 minutes. The truck's engine filter took about five. Its air box also uses clips, and the filter is large and flat. I tapped the old one on the driveway and a small cloud came out, which was all the proof I needed.
Why I bother
A clogged engine air filter on a modern fuel-injected engine doesn't hurt mileage as much as people used to think, because the computer adjusts. It can cost you some power and responsiveness, though, and it means dirt is working harder to get past it. The cabin filter matters more to the people in the van. It's what filters the pollen, road dust and whatever else comes through the vents, and a clogged one also makes the fan work harder and the air conditioning feel weaker. With Missouri's air conditioning season starting in May and running into September, that's not a small thing in our house.
I now have a line in the spreadsheet for both filters on both vehicles, with a reminder about once a year for the cabin filter and every other oil change to look at the engine filter. Looking is free. You pull it out, hold it up to a light, and if you can't see light through it, it's done.
The van smells like a van again, which is the best I can promise. Lainey has moved on to complaining about the radio, and that I can't fix with a $14 part.