I have a 1997 Mustang with the 3.8L engine in it. I just blew my head gasket out and replaced it myself. I am not the great of a mechanic but I am also know what I am doing. But anyway, I replaced everything and followed the torque specs, but when I went to install my rocker arms and push rods, I got all but one torqued quite right. I would get the Top Dead Center and get it torqued, then rotated the next and so on. Got all of the rocker arms torqued and then wanted to double check myself. All but one kept their torque. I tried getting that one again, and then rotated the engine over again and it loosened up again. I am now assuming that the hydraulic lifter is damaged in some way. I don't know if it lost its prime or not. I was hoping to find someone that knows what I can do to fix it. Thanks.