Am I the only one who sees guys cranking down air filters too tight?

I swapped out a filter on a Freightliner last week and the gasket was crushed flat from being overtightened. It lets unfiltered air into the engine, why do people keep doing this?

2 comments

2 Comments

hill.margaret6d ago

Used to be one of those guys who thought tighter was better... figured you wanted that seal really compressed. Then I saw a Cummins ISX with the gasket squeezed out on one side, dirt trail right past the filter housing. Cost the guy a rebuild at 200k miles. Changed my tune real quick after that... a quarter turn past snug is all you need, any more and you're just squishing the gasket flat.

max_torres445d ago

@hill.margaret you're right about not over tightening, but I gotta gently push back on that quarter turn rule. On some filters, especially the bigger spin-ons like a fleetguard on a 15 liter, the gasket needs a little more than that to seat proper. I've seen guys do the hand tight plus quarter turn and still have a weep after a few thousand miles. The trick is to feel the gasket contact first, then give it another half turn or until the rubber just starts to bulge a little at the edge. On the ISX you saw, that was probably a bad gasket from the start or someone used a cheater bar. The real lesson is to always lube the gasket with fresh oil and never, ever use a filter wrench unless you're taking it off.