Blown head gasket? This is my mom'* '94 Buick century with the 3100, 81k on the clock. It does have a collapsed lifter or something, thus the tick. But listen to how bad it runs, it has a strong hissing sound (not a sucking sound, but a blowing sound), no check engine light. LIM gaskets were replaced a while back, around 72k. NO oil in coolant or coolant in oil.