I bought a 1999 S10 Blazer . Had it about 3 months with no poblems . Today I started it up and had a rocker arm rattling real bad . I'm thinking O.K .I'm going to have to pull a valve cover cause it's getting louder by the second . I start it up and shut it off a few times and it seems to get worse , now I'm thinking bad things , like cam lobe wore off .I was going to put a little ATF in the oil to see if that would maybe free up the lifter if it was stuck . So I jump in my Scout, go to town to get a gasket just in case I pull the cover . My brother inlaw works at the NAPA parts store and told me to try this stuff called Sea Foam . I go home ,dump it in the crankcase ( looks like water , kind of didn't want to pour water in my oil ). Fire up the Blazer pull up a chair and in about 3 - 4 mins. the rocker stops rattling ! Took it for a spin and it runs fine , boy am I :happy: . This stuff must realy work. ___________________________ Gil.