Difference btwn hose types

I recently had a leaky coolant hose on my car (1988 Mitsubishi Starion). It wasn’t one of the big hoses going to/from the radiator, but rather a smaller diameter coolant hose going from the thermostat housing to the turbo.

I went to get a replacement from AutoZone, but the only hose they had w/ a similar diameter was a FUEL LINE hose (w/ 50psi rating).

I went ahead and bought that one and have been using it for abt a week now, but I’m curious as to what the true difference is in the makeup of coolant hoses and fuel hoses; and am I cool w/ the using the fuel hose, or should I seek a proper replacement meant for antifreeze?

You’re fine with the fuel hose for your purpose. A hose intended for fuel must be made from chemicals more oil-resistant than one intended for water (coolant) or vacuum purposes. In practice, automotive hoses for all purposes are generally made of the same inert synthetic rubber, although sometimes they may be marked as “not intended for…” or some such disclaimer. Also, vacuum hoses must have thicker walls than, say, windshield washer hoses. You may stick with what you have.