One way to find out if it's your heater core, is to leave the car idling at normal operating temp, and turn the heat on high; if both heater hoses are burning hot, your heater is probably fine (although it could be leaky which could explain the smell); if one of the hoses is cold or luke warm, your heater core is probably clogged. If there's a heater control valve in your system, make sure it's not stuck closed (the inlet hose will be hot up until the valve, and cold after the valve).
From what you're describing, it sounds like you need to flush your cooling system/heater core, and you may even have to replace the core depending if it's leaking or not. Again, if you have a heater control valve, make sure it's not the culprit. I can't remember if you have one or not.
Monday, May 22nd, 2017 AT 1:54 PM