When is air filter dirty?

[shagnat]

I bought a used Genny (2010 4.6L) w/36K miles. Unable to get any real service records I'm trying to figure out when an engine air filter needs replacement regarding how dirty it is.

I finally got the filter out and on the bottom side are several small bugs and several specs of dirt between the pleats. This filter isn't filthy at all, still kinda' white, but, surprised all the dirt is on the bottom of the filter. Anyway, how do I know if I should replace it now or just wait for another few thousand miles?

 

[NSXNEXT]

Cheap investment. Just pick up a new one and call it a day.

 

[upsbroke]

Go buy a new filter and compare it with yours.

The general thought is you should put the filter up against the light of the sun. If you have a hard time seeing the light come through- it might be time to put in that new filter

 

[Mark_888]

I bought a used Genny (2010 4.6L) w/36K miles. Unable to get any real service records I'm trying to figure out when an engine air filter needs replacement regarding how dirty it is.

I finally got the filter out and on the bottom side are several small bugs and several specs of dirt between the pleats. This filter isn't filthy at all, still kinda' white, but, surprised all the dirt is on the bottom of the filter. Anyway, how do I know if I should replace it now or just wait for another few thousand miles?

The air comes up from the bottom and out through the top hose into the engine. Best to vacuum out any dirt or debris under the filter in the ducts below, since they may eventually get deposited on the filter.

 

[shagnat]

Thanks for the replies. I had forgotten about the sun thingy.