Oil pickup tube o-ring replacement

[rdezs]

I have a separate question if anyone is reading this thread still. I have a friend I was telling the story to and he was "that happened to me too!" but he never solved it. It happened while on vacation, Tahoe loaded down with gear, driving in the mountains. No bubbles on the dipstick, just no pressure. He changed the pressure sender (he's on his third one) none of which changed anything in terms of it reading zero. The problem basically "went away" and has not happened again since being back home. I'm not sure at what point in his trip the alarms stopped blaring at him, and I should probably follow up and ask him that. But has anyone seen anything like this where it could be altitude related?

Never seen any indication of an oil pressure problem being altitude related. I would bet he probably had a piece of grit in the oil pressure relief valve in the oil pump, or the one in the pan.... It may have cleared itself out.