Posted on 9/29/2026
You lift the airbox lid expecting a dirty filter. What catches your attention instead is a dusty streak on the supposedly clean side, where air heads toward the engine. Perhaps the filter was replaced recently, and its pleats barely look used. Putting another filter in the same box doesn't explain how that dirt got there. Before cleaning anything, it's worth looking at where the dust collected. A trail around one corner, grit across the outlet, and a hole through the filter each point toward a different path. The old filter and its housing still offer evidence. First, Identify Which Side Should Be Dirty Air enters the housing on one side of the filter, passes through the filtering material, and leaves through the engine-side outlet. Leaves, insects, and road dust are expected on the incoming side. A dirty outer surface shows that the filter has been catching debris; it doesn't prove that dirt has passed through. Dust beyond the filter needs ... read more