Justin, Welcome to my own personal Terrain h e l l
This has happened not once, but twice on my vehicle. I have a 2010 terrain that has had nothing but problems, I have had so many things repaired but this issue is the worst.
At ~80,000KM travelling 120km/hour in -20 weather though the mountains my engine seized. I was towed back to the city ($300 at my expense) and the dealership found that the PCV had frozen, blown the real main seal and dumped all the oil. I had no warning lights and only realized I had a problem when going up a mountain pass engine made a horrible noise and stopped and I lost all power.
In this case it was still under normal drive train warranty and I got a new engine.
Fast forward ~60,000M after the new engine and the rear main seal blew again due to a plugged pcv valve. This time however I was going in for an oil change and it was noted that there was some excess oil under the engine. I did the oil change and went home. The next morning pulled out of my garage and saw a large pool of oil so drove right to the dealership. Luckily I caught it this time before I destroyed the engine but was still faced with a big bill. The dealership helped my out and ate some of the cost but I am still over $2K out of pocket.
I have been getting the run around from GM for almost a month now because I am fighting for them to compensate me based on the service bulletin but they too say that my VIN is not covered.. even though this has happened twice.
I am waiting for another call back from GM but if it is not to my satisfaction I am going to take this to the local media.
I hope you see this as I would like to discuss further with you. Looking through the web this seems to be a common issue and I really think GM is sweeping it under the rug.