Radiator leak?

That might be coolant. Are you using Dexcool? You can try Alumaseal or another sealant to see if it helps but seam leaks like that mean the radiator is getting ready to fail.

May have had dexcool before. Right now just Peak 50/50.

If color is reddish could be transmission fluid leaking from radiator the transmission cooler is made into radiator and transmission lines run to it to cool off transmission fluid.

The red colored fluid you see leaking is coolant. Check the weep hole on the bottom of the water pump. You will see the coolant leaking from there. The other option might be the O RING has finally hardened enough along with corrosion that it is leaking. Especially since its following you lower radiator hose to its lowest point in its loop. Never use a sealant to stop a leak. That's the mickey mouse way. A manufacturer never uses that option. A good mechanic finds the source if the leak and repairs it period. The 5.7 and the 4.7 engines use O rings to seal the water pump to the front cover. They are prone to leaking after many miles. Hope this helps. I can almost guarantee its not your radiator. And don't use any of the leak stop remedies. The leak will only get worse and you'll find yourself on the side of the road. Trust me, I have been a mechanic for many, many years.