It is getting cooler here in the Northeast. Did you turn on the heater or defroster? Coolant will not flow thru the heater core until you turn on the heater. If you have a leak it may not appear until you turn on the heater. Check the hoses and where they connect to the core that is exactly where you are seeing coolant.

 

Hey I'm a new Corvette owner myself. I have a 1979 L-82. I had a problem with a small coolant leak myself. If you have checked all the hoses clamps etc. Check and make sure your freeze plug on that side is not leaking. There are usually 4-6 of these on a 350. That's where I started and come to find out it was the back side (passenger side) Intake manifold had a small leak around the corner. So I had to take Dist, Valve Covers etc, and clean everything up and reseal it. Now its not leaking anymore. Mabye this will help

Anthony