Learn how to flush your heate.
Chemical to clean out heater core.
Slowly twist the hose back and forth while pulling to slide it off the outlet.
If the core was clogged expect the rest of the system to have plenty of buildup and it can simply re deposit in the core if it all wasn t cleaned out.
Remove heater core outlet hose.
As you do so the coolant water and grime within the system will be expelled through the inlet hose.
Add hot water into the same temporary hose to completely fill the heater core.
You may want to run a chemical flush in the system first to loosen the gunk up and then use hose pressure to flush out the radiator engine and heater core thoroughly.
You may have a clogged heater core so do a heater core flush and unclog it.
If the heater core is small or the core is.
I blasted air through each hose with the air compressor shooting it out of the top of the radiator filled with water and blasted it again over and over until it came out clear.
Pour r106 cooling system flush into the heater core using one of the temporary hoses.
Unless you are 100 sure the blockage is in the heater core you might be barking up the wrong tree.
Install temporary hoses onto the heater core nipples.
Is your heat not working or is your heater not hot.
Pull them back a few inches so that we can remove the hoses.
Be sure the hose is positioned so anything that comes out of it will pour into the container.
My point was that there could be blockage in another part of the cooling system other than the heater core that is causing your problem.
Cant get heat so was i was going to do a direct heater core backflush but cant get to the heater hoses to get them off and they make these clamps so hard to figure out sometimes so you cant do your own work.
Between each i covered my engine bay with plastic popped the radiator cap and pulled the hoses off my heater core up by the firewall.
Part 2 of 3.
Use pliers and pull the metal hose clamps back.
In order to clean the blockage out of the heater core you will need to force either air or water through the system.
Take care not to damage.