How do you flush the heater core on a 2000 Ford Expedition?

Answer 1

I use compressed air when I do it, but I also work in a shop.. you can use water if compressed air isn't available. There are two coolant lines which go into your firewall. Disconnect them at the most forward point on the vehicle. Stick one line into a jar. I like to use Liquid Plumber for this, but there are products specifically made for automotive use... liquid plumber is just as good as any... then, I take an air chuck hooked to compressed air, insert the end into the hose, take a host clamp to tighten the hose around the air chuck, and, after letting the Liquid Plumber sit for about 10 - 15 minutes, I hit it with compressed air until stuff stops coming out into the bottle which the other hose is placed into. In the absence of an air compressor, you can use water from a hose.