I'm posting this for a friend of mine. He has a 92' sts with a coolant leak that we can not track down. It's leaving a puddle under the driveside front tire. I am an experienced mechanic but am stumped on this one. Checked all the hoses and they are good, radiator looks to be doing well, doesn't appear to be leaking out of the side tanks. Is this a common problem or freak of nature. It appears to only leak after it has sit for a bit after thoroughly warming up. Thanks for all the help guys.

I had a similar problem, check the sealant you can get from a GM dealership, it's in your owners manual. The leak is coming from
the bottom of the waterpump, it's real hard to see and it runs along the bottom of the engine and exhaust. If it's the same leak I had. I hope this helps.