Radiator cap? coolant leak

Darwins Child

Thanks for the input. You may be right about the aluminum spreading or a bad hose clamp. Thanks for the recommendations for testing.

The thing I find interesting is that if coolant is leaking / spitting from between the cap's rubber gasket and the aluminum sealing surface that it is pressing against, I would expect to see some remnant of coolant at least somewhere on the gasket-side surface of the cap that is directly adjacent to the gasket.

But, as you can see on the photo of that gasket-side area, there is none, even on the downward-pointing edge of the cap or any of the aluminum just outside of the convex sealing surface, which is weird. I should have noticed whether this was also the case on the original cap, but, once again, I, as well as the tech who did the pre-purchase inspection, may have made a mistake in assuming that it was the cap that was leaking.

Thanks again.