Going to add some coolant Monday and see if that helps. In the meanwhile, anyone know how I can check my heater core to see if that's what's gone bad?

 

Add the coolant , then run the car with the heat on full. Then check the level, you might need to add more.

 

Just be sure to heed the warning on the cap. Never remove it when the coolant tank is hotter than you can touch with a bare hand.

 

But of course. From my experience you don't have let the engine warm up. Turning the heat up is just to get coolant into the heater core circuit.

 

Added the coolant, turned it on and started to feel some heat. Added more coolant the next morning since it was still on low and now heat is working 100%! Thanks for the help guys.

 

Where should the coolant level be when cold?

My 2011 recently experienced the loss of heat - brought it in to the dealer and they could find nothing wrong - checked the pump and pressure tested the system. They added coolant and everything is working fine.

At the moment, when the car is cold it sits at the low line. When fully warmed it sits at the max line.

Do i need to add distilled water / coolant so that it sits at the max line when the car is cold?