I just had my Diesel oil changed at 12000 mi. and notice the air filter was totally black. My new owners manual does'nt say how often to change it. Is this normal? Dave

 

Yes, it is normal. I recommend changing the air filter and fuel filter at 10k mile intervals.

MikeyB

 

What did the restriction indicator say? Eyeballing is a very poor way to tell whether a filter needs to be replaced.

The dirtiest air your engine will ever see is with a new air filter.

 

what is a restriction indicator?

 

There's a little gizmo mounted on the air box. It has a spring loaded plunger that moves under vacuum, indicating how restricted the filter is, and when to replace it.

The plunger doesn't return until you push the reset button, so you can read it when the engine is not running... Just push the reset when you replace the air filter.