I noticed all these cracks before I bought this junkyard radiator. But since the truck wasn't wrecked, and there are no signs of coolant leaks or overheating, and they only appear on the rear face of the hot side, I decided they must simply be from the sealant cooking & curling away. Since it's holding ~12psi right now, they're fine.

Owner caption September 2012 · Photo 4709 of 5000