major oil leaks that would require reseal of front engine cover 2013 CTS Caddy

The engine's in these vehicles are prone to engine oil leaks. I'm not even sure which engine you have in your CTS, but I can say that Cadillac engines typically leak oil. What causes it? Possible design flaw? Possible internal engine crankcase pressure being excessive? Really no way to know. If it's my car, I get a different car. But that's my opinion based on my previous experience with this vintage of Cadillac. Good luck.