A build up of dirt in the intake area is probably common because of the way the air intake cover is made. Over time the biggest single leak in the intake forms at the mounting to the fuel distributor intake. The o-ring seal is just not big enough to keep a seal. Also, I believe that over time, the plastic housing looses shape and air is drawn in around the seal. A fairly respectable fix is to put a hose clamp around the air filter box mounting horn (I don't know what else to call it) and after installation tighten it down easily to get some closure. I tightened the clamp slightly couple of times over a week or so and eventually got a good seal. It takes a little time to reform the plastic - it doesn't take much. The amount of dirt accumulation has dropped to nil. I noticed the last time I change the air filter there was virtually nothing to clean off. A seal with a larger thickness would probably work too but I could never find one that would stay in the grove. Harold McElraft - 3354