Unpopular opinion: I think the whole "air filter is fine until it looks dirty" thing is way overblown

I had a truck come into the shop a few months back, a 2015 Freightliner Cascadia, and the owner swore his air filter was fine. He said he pulled it out and held it up to a shop light and could see through it just fine. I told him to just let me swap it anyway, and he argued with me for like ten minutes. I finally just did it to shut him up. Took the old one off and laid it on the concrete, and that thing looked totally clean. But when I tapped it against the ground, a huge cloud of dust shot out that you couldn't even see in the folds. It took me about 3 extra hours of testing to find a random boost leak that was caused by the restriction running the turbo way too hard. Has anyone else found that a "good" looking filter was actually wrecking your numbers?

2 comments

2 Comments

alicem2915d ago

Gotta love it when a filter pulling triple duty as a dust bong gets a clean bill of health. Had a buddy argue the same thing with his pickup, filter looked pristine until I smacked it on the gravel and watched a dust cloud that would make a Sahara storm jealous. The real kicker is that your turbo was basically trying to breathe through a vacuum cleaner bag. That extra time chasing a phantom boost leak sounds like a nightmare but at least you didn't blow up the engine.

finleyfox14d ago

Watching people swear by a "clean" air filter that's actually clogged makes me think about how many things in life we judge wrong just by looking at the surface. A buddy of mine insists his tires are fine because they've still got tread, but I can see dry rot cracks between the treads from ten feet away. Same thing with people who check their oil and it looks dark so they think it's dirty, but fresh diesel oil turns black in like 50 miles. We've all got that friend who thinks their phone battery is fine because it still holds a charge for a few hours, but it dies at 30% when it gets cold. What other things do you think people misjudge just by glancing at the outside?