Cadillac Repair: coolant leak in 96 STS Caddy, radiator pressure tester, coolant leak

Question
I have a coolant leak that began as a slight odor, progressed to a low  coolant condition, became a slight puddle, then went to a full leak, even with no engine running.  While I am told it is the awful head gasket, I don't believe it.  It never overheated. I periodically saw smoke, as in burning coolant come from under the hood, but never could track it down.  This massive leak seems to be coming from the firewall section of the engine. I can't see what's there to leak.  Intake manifold leak was also suggested.  Any idea on what it could be?

Answer
The easiest way to find the leak is to go to an auto parts store such as AUTOZONE where they lend tools and rent a RADIATOR PRESSURE TESTER which is simply an air pump with a radiator cap fitting on the end of the hose and remove your radiator cap and pump up the air pump by hand to approx 15 lbs with the engine OFF and start looking for the leak.