slomatt
10-17-2012, 02:59 PM
As we know 3rd gen 4Runners do not have a factory option for a cabin air filter, which is a bit annoying on long dusty trail runs. On a Jeep I used to own I put a HEPA filter on the air intakes in the cowl which helped a bit, but since it was exposed to the elements the filter degraded quickly.
This weekend I happened to have the front passenger carpet pulled out of my 4Runner because a friend dumped an entire 64oz lemonade in there and I was cleaning things out. While I had the carpet out I decided to clean the blower fan so I removed the glove box and the fan.
The blower fan is a "squirrel cage design" that fits into a circular housing, it pulls air in from a ~4" hole at the top and shoots it out the side. Above the fan is the blockoff plate that switches between recirc and fresh air mode. What is interesting is that the blockoff plate is in a square enclosure and there is about 2" of space between it and the blower intake hole. I think you could fit a 1" tall HEPA filter in here without obstructing operation of the recirc valve. The filter would have to be squeezed in through the ~4" hole, and then you'd have to find a way to hold it to the bottom of the box so it seals. The air flow will suck it down, and I'm wondering if some magnets would do the rest.
This setup seems promising, and I have a HEPA filter so I'm going to test it out over the next few days. If it works this could be a great way to cut down on the amount of dust that is pulled into the truck.
Below are some really horrible photos from my phone looking up into the fan shroud in free air mode first and recirc mode second. It's hard to see, but above the circular opening there is a roughly 8x8x2 opening where the filter could sit.
- Matt
This weekend I happened to have the front passenger carpet pulled out of my 4Runner because a friend dumped an entire 64oz lemonade in there and I was cleaning things out. While I had the carpet out I decided to clean the blower fan so I removed the glove box and the fan.
The blower fan is a "squirrel cage design" that fits into a circular housing, it pulls air in from a ~4" hole at the top and shoots it out the side. Above the fan is the blockoff plate that switches between recirc and fresh air mode. What is interesting is that the blockoff plate is in a square enclosure and there is about 2" of space between it and the blower intake hole. I think you could fit a 1" tall HEPA filter in here without obstructing operation of the recirc valve. The filter would have to be squeezed in through the ~4" hole, and then you'd have to find a way to hold it to the bottom of the box so it seals. The air flow will suck it down, and I'm wondering if some magnets would do the rest.
This setup seems promising, and I have a HEPA filter so I'm going to test it out over the next few days. If it works this could be a great way to cut down on the amount of dust that is pulled into the truck.
Below are some really horrible photos from my phone looking up into the fan shroud in free air mode first and recirc mode second. It's hard to see, but above the circular opening there is a roughly 8x8x2 opening where the filter could sit.
- Matt