I've tried searching on in cabin air filter on the '98 QX4, but all I can find

[meyersk76]

is that the '99 and earlier models did not have them. If that's the case were they built not to need the incabins? I don't want to go cutting for no reason. I took a peek at the cooling unit stuff in there, and didn't notice but a couple of leaves and a pine straw. Why is it not dirtier? There's a 150K+ on this. Should I just return the filters? Anyone?Thanks!

[Pianodemon]

I too bought cabin filters for my '98 Pathy only to find that there are none there (after I removed the glove box per the sticky post in the DIYs).

Guess it might be an after-market mod?

[Pwnin O'Brien]

It's not an aftermarket mod, some Pathfinders simply did not come with the cabin filter pre-installed. You would need to cut the opening for them and install them yourself. I believe there are instructions floating around somewhere on NICO. It's pretty simple to add them.

[meyersk76]

True. But my main question is what's the point if it was built this way without one and 2nd, when I looked in and around the cooling unit and where a filter "would" be, it was clean of debris after 150K miles. I just closed it back up because I didn't feel like cutting away at something that may not necessarily need to be. I dunno, maybe the '98 QX4's airway tubes/engine filter is formatted differently?

[Pwnin O'Brien]

True. But my main question is what's the point if it was built this way without one and 2nd, when I looked in and around the cooling unit and where a filter "would" be, it was clean of debris after 150K miles. I just closed it back up because I didn't feel like cutting away at something that may not necessarily need to be. I dunno, maybe the '98 QX4's airway tubes/engine filter is formatted differently?

The in-cabin air filter was an option on all R50's (just like leather was an option, or the Bose audio system was an option). You had to pay extra for the in-cabin air filters to come pre-installed on your vehicle. Not having the filters won't damage anything and you may not even notice the difference at all. You shouldn't expect to see any large debris or any sticks or twigs in the air box, even if it got to the fan the fan would have just push it onto the heater core and you wouldn't be able to see that. The in cabin air filter is really for people with allergies or people who drive their vehicle in a sandy/dusty area. To be honest, if you really don't care to have an in-cabin filer than I would not recommend installing one, they can cause issues with other HVAC components if not replaced often (namely the fan amplifier or fan resistors, a clogged filter will prevent the cooling of the two which leads to premature failure and subsequent replacement).