Using oil

My car has started using lots of oil. It never used much oil before and it does not seem to be burning oil. There are no signs of leakage. What could be the problem?

When the motor is cold take off the radiator cap and look for oily water, if so head gasket is leaking.

Doesn’t this car have the Northstar engine?
If it does, there is a really strong probability that the intake manifold gasket is the problem.

“Lots of oil” is rather subjective. How many miles on the car, and how many miles of driving does it take for the engine to lose a quart?