As I mentioned in some one else's thread last week, I thought I needed to replace my heater control valve because a I felt that it may be a restriction in the line. On further inspection I feel I was right. The inside of the valve is quite simple and all rusted. It wasn't opening as far as when it was installed originally and it leaked past the seat when closed. Well NAPA did not show a listing for it so Paul (the owner) went thru his picture catalog and produced a fitting replacement. It was 16 bucks and all plastic. I needed a little more heater hose to make up for the shorter valve but it works, so far. The NAPA part number is 660-1200. If you decide to try one, it only goes in one way. There is a flow arrow on the side.