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The cabin filter helps keep dirty outside air out of your HVAC and dirt from being blown all over your face and interior. The filter is located behind your glove box, the owner's manual has instructions on replacing it. An easy to way to test if it needs changing (as suggested by Toyota) is if your windows fog up really easy, then it needs to be changed. How dirty this filter gets depends on where you drive and how much you use the ventilation system. The more you use it, the more air gets drawn through the filter. If you keep the car in recirculate, that'll probably extend the cabin filter the longest, since you would have minimal amounts of air flowing through it.
The engine air filter keeps dirt from entering your engine air intake. This filter is located to the left of the V6 engine cover looking at the truck from in front of it. Follow the tube that goes from the passenger side fender to above the left side (again, looking from the front) of the engine. Unsnap the clips, slide the airbox back a bit and you can pull the filter out. I change my air filter when I can't see light passing through it when I hold it under a light. How often the engine filter is changed depends on if you drive on dirt/dusty roads or mainly highways in an urban area.
Here's the information from
toyotaownersonline.com for the 35k mile service interval:
[QUOTE] Replace engine oil and oil filter 1
Rotate tires
Visually inspect brake linings/drums and brake pads/discs
Additional Maintenance Items for Special Operating Conditions:
Driving on Salt-Covered Roads
Lubricate propeller shaft (4WD)
Re-torque propeller shaft bolt
Driving While Towing
Lubricate propeller shaft (4WD)
Re-torque propeller shaft bolt
Tighten nuts and bolts on chassis
Driving in Desert or On Dirt Roads
Inspect ball joints and dust covers
Inspect drive shaft boots (4WD)
Inspect engine air filter
Inspect steering linkage and boots
Lubricate propeller shaft (4WD)
Re-torque propeller shaft bolt
Tighten nuts and bolts on chassis
Applicable Footnotes:
1) Reset the oil replacement reminder (