I have a distinct coolant smell inside my Jeep (2009, 60k miles). I popped the hood and couldn’t spot any leaks nor was there any fluid underneath the vehicle. I took it into a mechanic and they smelled the same thing and put the coolant system under pressure (as well as doing a visual inspection), and could not find any leaks nor was there any evidence of fluid by the vents. They also noted that my coolant levels were still full and I had not added anything to the car. The current theory is a pinhole leak in the heater core (the smell is definitely worse after the car has been driven a bit).
I have had one suggestion to add Bar’s Stop Leak to the radiator, but the mechanic said this was a Bad Idea (his argument being that since there was no visible leak in the system it would likely just gum things up). Since the vehicle seems to be otherwise operating fine, I’m hesitant to replace the heater core, but there’s a good chance it’s still under warranty, so I could go that route.
So, could it be something other than the heater core? Should I have that replaced or would the Stop Leak be a good idea?