One problem related to engine head gasket failure has been reported for the 2009 Infiniti G37. The most recently reported issues are listed below.
Rear galley gasket failure, vehicle is out of warranty, but only has 56k miles on the engine. Is daily driven and not used for any driving outside of the day to day routine. Contacted the dealership and while they see these gasket failures often they were unable to do any type of work on the vehicle due to it being outside of the warranty. The fix will be to replace the gasket which will be a 4,000$ repair, on a car that is only 9 years old and has low miles. This failure occurred while my wife was driving and instantly threw the car into limp mode, because of the lowered oil pressure reading, which resulted in a car unable to continue highway speeds and without knowledge of what limp mode was and what was occurring this could be a very dangerous situation that appears to be a common failure in the vq37vhr engine. I was surprised this isn't already a recall issue.