the cylinder is right there about 1/2 to 3/4 inches. I use a coat hanger size wire and probe all over the place. Poke around until you get the clog free and then keep probing until clean water comes out. I've done several of them, and that's the only way I know how to do it with the engine in the truck and no plans to remove anything in the near future. Patience and fortitude!
