I just replaced my Oil Guard return to oil pan with their updated return to the the filler cap, it looks like a better setup, as as I'am not fighting the the oil pan return pressures vs. returning thru the the fill cap. The old filters were sooted, very heavy, at 4,000 miles (oil pan return, maybe lack of pressure) just wondering. The new system is Valve cover (filler) return. I'll know in 4,000 miles. I'll let know then. (Oil Guard did not give a break on the what I would consider a correct (right) setup - shame on them) So be where my friends.