Besides if you follow the directions the chemical flush should be safe for the whole cooling system.
Chemical to clean out heater core.
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.
Remove heater core outlet hose.
Part 2 of 3.
Use pliers and pull the metal hose clamps back.
Learn how to flush your heate.
Pull them back a few inches so that we can remove the hoses.
You may have a clogged heater core so do a heater core flush and unclog it.
Is your heat not working or is your heater not hot.
Allow to sit for 1 hour.
In order to clean the blockage out of the heater core you will need to force either air or water through the system.
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.
Take care not to damage.
If the heater core is small or the core is.
Be sure the hose is positioned so anything that comes out of it will pour into the container.
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.
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.
Slowly twist the hose back and forth while pulling to slide it off the outlet.
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.
If i do a radiator flush as you suggested will that clean my heater core at all and how well in comparison to a direct back flush.
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.
