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.

I was leaking antifreeze a while back. Ended up just being a hose clamp. Mine was leaking in the same area too.

not likely a head gasket - at least we have not seem those yet.

most common issue with aging LSes is hairline cracks in the coolant reservior tank (degauss bottle) and the smell could be the valve cover gaskets (another common issue).

I have replaced both of the valve cover gaskets at around 120,000. Could they be bad again already?

check the reservoir, that's what it was on mine. it had a crack that you couldn't see unless you actually removed it.

It was the coolant tank. 2 nice size cracks in it. Luckily no head damage. WHEW!!!!

:Beer

speaking on that i notice some coolant leaking out but i took it to a mechanic and it stopped leaking anyways im thinking its a hose or something well im going to have it replaced one more thing its 2 hoses that connect to the coolant reservoir the one that uses atf fluid.

Be cautious because that is how mine started too. Just a small amount of coolant behind the driver's wheel. Nothing consistent but I didn't take to the warning sign. I got lucky and it didn't cost me big. Be careful with yours as well. Thanks for the cheers Quik LS. :)