I have a 2000 LS with the V8. I have 149,000 miles on it. Recently I have noticed two things. One, the smell of exhaust being sucked in through the vents and I am loosing coolant somehow. I have seen coolant slowly leak from under the driver's side of the engine on 2 occasions. However it wasn't very much. But today(4/20) I drove it for approximately 4 miles and the temp gauge went to hot. I immediately pulled over and let it cool off. It again was low on coolant. Am I looking at a blown head gasket? No smoke from the exhaust whatsoever.