I have an old 97’ Expedition that has a leaking heater core. It needs to be repaired but the cost it more than the value of this old vehicle. It has 274, 000 miles on it. Mist is coming from the vents now and i saw coolant dripping down on the floor mat on the passenger side. I was told to try a Bars Leak but i’m not too sure if that s a good idea. I heard that stuff get into every crevice and eventually the car can overheat down the road or ruin your head gaskets. Any thoughts on this?