My buddy has a 2001 Cobra. He changed his oil this weekend and when he unscrewed the filter antifreeze ran out. It was just a drip but it was there none the less. He said and ive heard a rattle on start up. It only does it for a second, but when at hwy speed it sounds like cheap gas. Kinda like the valves and if he touches the gas it stops. We think a blown head gasket, but there is no water in the oil. Is there something else it could be, or is he screwed? Probablly doesnt matter but the car has about 60k on it.