91 pontiac firefly

[over the hill]

Bought this 91 firefly with 118000 klms. Drove it 600 miles over the rockies and it used about halve a pint of oil. one day I drove it 6 miles in 4th gear up a hill
at 40-45 mph and when I stopped there was oil blown all over the engine, top to bottom. Took 2 quarts to fill it. Drove home, it did,t use oil. I have driven about another 300 miles since & no problem.
I cleaned the engine and can,t see any leaks. By the way the filler cap was not left loose !!!!. Soooo has anybody got any ideas ? Engine vent system,?
PCV valve ? Any help would be much appreciated .
Thanks ahead of time !! Signed Over The Hill

[*SMOKE*]

This is only a guess, if the hill was steep enough the oil may have pooled in the head and could have come out the cam seal or even the oil cap if to much was in the valve cover at once. I had a 90 geo metro which I took 1800mi from Nebraska to Yellowstone NP and back without any major isssues.