Not very likely since the heater core only holds maby a quart of liquid and the rest of the system has just been flushed. Most likely if he reverses his lines when it comes out it will hit the impeller of the water pump get broke down and settle down in the block somewhere. With wind chills like my house -40 that is a 5 min repair vs anything else he could do. Besides if he is getting warm air out it is not that clogged up

 

did a radiator flush last night,(I also lost my heat the night before)I noticed on the 2nd flush ,I still had no heat!! So I took the heater core hose (return) off at the manifold,disconected the inlet hose by the fire wall. then I filled the return line with water then used my air compresser to blow the water threw(be sure to put a rag by the fire wall to stop the water from hitting yourself on the shirt!!!)I did this back and forth a couple of times,alot of crusty crud came out.Hooked her back up and now have some of the best heat around!!!No more drexcol for me!!!! PS I used the airline because my water hose is froze!!!!!!!!

 

Not very likely and never gonna happen are two very different things in my mind. With the amount of junk that I have seen come out of a marginally working heater core, I would not want that anywhere in my cooling system. A heater core can have a ton of junk in it and still put out mediocre heat.

You could use the power of the water pump on the engine to help you, but you may need to get some more heater hose to reach to a bucket. Take the line that goes off of the pump and swap it to the opposite port. Take the other hose and cap it off. Then put your new hose on to the empty heater core outlet and direct it into a bucket. You would need to make up the difference of what was pushed out of the system, but this would effectively back flush the heater core.

 

You got lucky because most people forget that the max psi of most heater core or radiator is 20 psi when you force more pressure through them them tend to leak. But glad you got it working

 

The heat in the blazer got to where it wasd ice cold so I had to get creative. I dissconnected the hot water hose from my washing machine in the basement and hooked my garden hose to it and ran it through the basement window, through the garage and to the driveway. I dissconnected both the hoses from the manifold and the water pump, abd flushed back and forth between the two and it was like the poor thing just puked brownpoop for a little bit and then ran clear as could be. I hooked the hoses back up, topped off the antifreeze, and now the heat gets nice and roast your butt out kinda hot. It's nice. I want to thank everyone for their tips and advice.