Time to change air filter in Altima 2.5?

[DaveInLA]

2002 Altima 2.5, 15K miles
I opened the air filter box and removed the air filter to take a look at it. A quick glance reveals that it's covered in soot, but upon further inspection, I can see that the tips of the ridges are really dirty, but the actual folds between the ridges are pretty clean. I live in metropolitan Los Angeles so there's supposed to be a lot of pollution here. Should I change the air filter? Thanks

 

[rpn453]

I change mine every 30K miles, as specified in the owner's manual. Filter change intervals listed in the owner's manual are usually conservative, so I'd recommend following that.

 

[jmacmaster]

It doesn't sound to me like its dirty enough to replace. Bang it a few times against something hard to knock as much of the dirt off as you can. I'd then keep using it. You can't go by an Owner's Manual statement of replacing it every X number of miles. Driving conditions and the roads you drive on determine how dirty the filter gets and thus how often you have to replace it, as does where the filter's placed in the engine compartment and how easy it is for dirt to get at it.

Where I live I interchangeably drove a 79 Dodge pickup and a 90 Dodge pickup for about 11 years. The 79 had a carb with the air cleaner housing on top of the carb with an air cleaner in it. This was the old circular type of cleaner with a big hole in the center and when you took the top of the air filter housing off you could see the top of the carb through the hole in the air cleaner. A snout attached to the outside of the air cleaner housing pointed forward and that's where air for the carb entered. The 90 Dodge had the modern airbox with an air filter inside type of setup and the airbox was behind the engine. I had to replace the air cleaner in the 79 Dodge about every 3-5,000 miles, but only had to replace the air cleaner in the 90 Dodge about every 45-55,000 miles.

 

[DaveInLA]

So when an air filter is dirty enough to replace, EVERYTHING will be covered in soot? Even the actual folds themselves?

 

[jmacmaster]

Usually, yes. But some parts may have more dirt than others. For example, as you've noticed on yours, the edges of the pleats may be dirtier than the valleys. On some filters, the outside gets dirtier than the center, or vica-versa. Its a judgment call. Knock as much dirt off as you can, hold the filter element up to the sun and see how easy it is to look through it. See if you can easily blow gently through it. If in doubt, get a new filter. Another test is that if your vehicle seems sluggish when it didn't used to be when accelerating, it may be the air filter's not letting enough air through and needs to be replaced.