i used an 8" piece of 4" pvc, two caps, two 5/8" hose barb's with threads on one end, a drain **** like what's on a radiator and a furnace filter. i assembled it with one barb at the top and one at the bottom like a Z and the drain at the bottom with several layers of 4" circles of furnace filter. that was my first version and looks to work pretty well. my next is the same way but with a screw in plug at the bottom like in the link above to replace the filter's. also, if you run it into yor exhaust you'll most likely have a nice little oil slick down the side of your truck. $0.02