That looks like coolant leaking past the head bolts. I like to use a brush-on sealant on the bolt threads and a dab under the head of the bolt. It's possible for coolant to follow the threads and seep under the bolt head even with the right torque on the bolts. Pull the head bolts one at a time, clean them up on a wire wheel buffer, and paint a little sealer on before reinstalling them. You might manage to stop the seep leaks without taking the heads all the way off. I like to use Permatex Super 300.
Jerry


"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!