K&N intake air system

If you are getting sand through ANY filter, it isn't a filter. The fine dust that is the issue with the oiled filters is almost the same size and the particulate in diesels. Wipe your finger on the inside of the intake after the filter, and compare that to the inside of the exhaust tip (pre dpf trucks). The egr particulate is always there - as long as the truck is up to temp - the dust passed from the filter varies, usually there is none, as most pavement driving is in clear air.