alright..so my car was just in the shop to put on a new manifold..to hopefully get rid of the exhuast leak..when i got the car back..the leak noise was still there..but not as loud as b4..so i check if there is any loose bolts..i find 1 loose bolt..so i decide to tighten it..as im tightening it..it doesnt seem like its getting any tighter..it just keeps twisting?? do i need a new stud on there????