My EV has head oil lines that thread onto spigots on the heads. They're on the inboard side of the heads and sort of underneath the valve cover area. So they are hard to inspect in situ without mirrors. One of mine started leaking on a trip and bled out for several thousand miles before I traced the source. It looked like a hemorrhage, but there was in fact very little escaping. As it turned out, it was the spigot loose in the head, not the hose loose on the spigot.