I have a 2001 Mitsubishi Galant and I only get heat when I'm driving, when I stop NO heat comes out of the vents. I had the radiator flushed out and I was told that the radiator had a lot of rust inside. What could be the problem?
There might be an internal coolant leak. See a mechanic for how to fix the leak if you have one. Also, the heater core is basically a small radiator inside the dashboard, so I would suspect your heater core is restricted with what ever this chunky stuff is hampering your heater operation. You might be able to remove both heater hoses under the hood and flush out your heater core with a water hose to remove any loose debris that is lodged in there.