I have a 2013 Challenger R/T that I bought new. It currently has 30,000 miles. It is the 5.7 L engine. In the last 6 months, I have been smelling hot/burned coolant. I marked my overfill bottle and noticed that coolant is disappearing. However, there are no visible leaks. I do notice burned coolant at the front of the engine between the driver's head and intake manifold/block area. I have also been getting oxygen sensor codes being thrown every month or so--the check engine light typically goes away. The code indicates the o2 sensor is on the same side of the engine that I see burnt coolant. I'm worried that I have a blown head gasket that is leaking slowly out of that corner of the head. Any thoughts?