what are the tall tale signs that a head gasket is blown? I have an 'exhaust leak sound' around nbrs 1,2,3....but i just put the stock exhaust system back in and maybe didn't tighten the nuts on the exh manifold enuf, or didn't tighten the connection of exh mfld to exh system enuf .............? please let it be a exhaust leak.... car has 87k miles on it,,...but sat still for 9 years..