Cadillac Tech Tips - How to fix it Discussion, Homemade Heater Core Flushing Tool in Item Specific Cadillac Discussion; If anyone is looking to flush their heater core, this contraption is very effective. You end up flushing the core ...
If anyone is looking to flush their heater core, this contraption is very effective. You end up flushing the core with water and air bubbles which is very good at dislodging sediment. I backward flow flushed mine using this method, removed alot of junk and got my heat working again.
Two 6' lengths of heater hose. One inlet size, one outlet size. Mine happen to be 3/4" and 5/8" respectively.
Simple shop air blow gun kit. I used a Kobalt kit from Lowes
Shop air. I used a regulated 20 PSI source
Female garden hose replacement end to fit the outlet size heater hose. For me this was 5/8"
1) Disconnect both heater hoses at the firewall. A hose clamp tool J 37097-A or similar makes removal of spring type clamps easier.
2) Connect your lengths of hose to the heater core inlet and outlet pipes. FYI, inlet will be the larger diameter of the two.
3) Insert the female hose end into the hose going to the outlet pipe
4) Using an awl, punch a hole in the end of the hose about an inch or so in past the end. You'll be injecting the air here.
5) Install the barbed tip in the blow gun, push it into the hole you made and connect the garden hose
6) Turn the garden hose on slowly then introduce the air and a backward flushing of the core will begin. If you want to see what you're removing, place the other heater hose (normally the inlet) into a clean bucket and clamp it to the edge to keep it from jumping out.