Kenpilot

Hey guys, I was changing out the engine air filter on a friend's 2015 RX350 and noticed what looks like a second "permanent" air filter installed in the back of the air cleaner assembly. I'm not a mechanic but have been working on cars for years and have never seen one of these before. The car has about 140,000 miles on it and it looks pretty dirty, and they mentioned their gas mileage recently as started to deteriate. I've checked the tire pressures, changed the spark plugs about 50,000 miles ago and changed the air filter. Is there any way to replace this other "filter" or clean it? I've looked all over the internet and the forums and part diagrams and I can't find anything mentioning this other "filter". Thanks for any info!!

ColAngus

Got a picture? I think I recall seeing a screen somewhere in the filter housing that looks like it's just supposed to keep dead leaves out.

Brownd3max

I too just noticed this today whilst checking the air filter on my newly just-acquired '15 RX350. It appears that the mesh has a fabric behind it as well. I too wonder if it's cleanable?

Kenpilot

carguy75

To my understanding. That is a charcoal filter media that absorb fuel emissions that may be sucked back into the engine. Basically an emission control filter. Some owners remove them for better performance in various models from all brands that has the built-in filter.

Kenpilot

Ah okay! Thanks for the responses everyone. I'll probably just leave it in there as it probably isn't effecting the gas mileage at all.

RX in NC

You may want to carefully clean it with a shop vac to see if that makes any difference.

Brownd3max

After watching some videos of this "filter" it has become clear what the original(C.A.R.B.) intent of this was(is). It's not really cleanable for one thing. And a dyno test that compared with & without it on a 4-cyl. showed about ~4-5 H.P, gain without it. Sooo...?

carguy75

LOL. I was considering removing the emission filter when I lasted changed my air filter, but I really do not care about increasing HP in my RX350 to go through the trouble.

C2J

Took mine out a while ago. No real difference other than a little better sound.