1998 Blazer No Heat

My 1998 Blazer would not heat. I had to replace the Heater core back in the Spring 6 months ago so I did think the core was glogged. Checked several things in the heating system, but everything checked out good. I felt thr two hoses going to the heater core and one was much cooler than the other. I pulled the two hoses and flushed the heater core out and chunks came out. Go figure, GM should have not changed coolants.

Heater works great now.

PS. If you ever have to change out a heater core on a 1998 blazer it's an all day if not two job the first time. The entire dash has to come out, the RH tire and inside fender have to be removed, and there are several bolts hidden on the firewall and there was that one bolt that took me almost 6 hours to find. You have to split the A/C housing on the firewall and its hidding behind the A/C core on the firewall.

First of all, did you replace the coolant when you swapped in the new core?

Have you every had the system professioanlly acid reverse flushed to clean the whole system?

What is the temperature gauge reading when the engine is hot and up to temperature?

1/4? 1/2?