HI JAMES JUST TO ELABORATE ON THE FILTER VLVING A BIT AS YOU KNOW MOST ALL OIL FILTERS NO MATTER WHO MAKES THEM HAS A VLV THAT IS SUPPOSSED TO BYPASS IF THE FILTER STARTS TO GET PLUGGED UP, ALSO THERE IS OR CAN BE DEPENDING ON THE FILTER MANUFACTURER ANOTHER VLV IN THE TOP OR OPPOSITE END OF WHERE THE FILTER SCREWS ON, A SMALL VLV IN THERE IS USED TO PREVENT DRAIN BACK , SOMETIME WHEN YOU CAN , TAKE A FLASHLITE AND SHINE IT DONW IN THE OIL FILTER TO THE TOP AND IF YOU SEE A LITTLE STRAP OF METAL THAT STICKE UP ABOUT 1/2 TO 5/8 INCH IT LOOKS MORE LIKE A MIDGET HORSESHOE WITH THE ENDS WELDED TO THE CAN AND SOMTIME YOU CAN SEE THE SPRING FOR THE VLV RIGHT AT THE EDGES OF THE SMALL STRAP , THIS IS THE ANTIDRAIN BACK VLV AND A LOT OF FILTERS DON,T HAVE THEM, USUALLY IF THE FILTER IS SCREWED ONTO THE ENG HANGING STRAIGHT DOWN OR ON A SLIGHT INCLINE THEY WON,T DRAIN COMPLETELY WHEN THE PRESSURE IS TAKEN AWAY SO THEY FILL UP PRETTY QUICK THIS WAY , BUT IN THE CASE OF MOST ISUZU DSL THE FILTER IS UPSIDE DOWN SO , IF YOU HAVE HAVE A VLV IN IT IT WILL DRAIN DOWN WHEN THE ENG IS SHUT OFF AND IT MAY TAKE A COUPLE OF SECONDS TO FILL,, AS I WAS TELLING SPENCER WHEN YOU GET READY TO CHANGE THE OIL ON ONE OF THESE IF YOU WILL TAKE A LONG SCREWDRIVER AND PUNCH A HOLE IN THE TOP OF THE FILTER OVER CLOSE TO THE SIDE IT WILL LET THE FILTER DRAIN MUCH MORE QUICKLY AND NOT MAKE AS MUCH OF A MESS WHEN YOU UNSCREW IT WISH WE HAD SOME OF YOUR DSL S HERE , I WOULD NEVER USE ANY FILTER WITHOUT THE DRAIN BACK VLV WEATHER THE ENG NEEDED IT OR NOT , BUT A LOT OF THE AFTERMARKET ONES DON,T USE THEM JERRY