Today I tried to get as much of the Bars Leak that I used a month ago to try to stop my '95 Integra GS-R radiator from leaking. I also wanted to use a proprylene glycol coolant (Preston LowTox). It's never below freezing, and it doesn't get hot enough that I worry much about boilover.
I had an old bottle of Sierra cooling system flush. After draining the system (incl the engine block), I followed the directions, which were turn on the heater, and run it for 30 minutes. I did just that (heater at max, fan at lowest level), and left it running in the garage for 30 minutes. I got back in 30 minutes and checked. The radiator cap and lower radiator hose were cool to the touch, but the engine and upper rad hose were hot. I saw the coolant temp gauge was slightly below the normal running temp.
I figure that with the heater all the way, the engine wasn't generating enough heat for the thermostat to open. I just drove it for 30 minutes. I always thought it took a long time for my Integra to warm up, and since I got another car, it seems really long in comparison.
I also miscalculated the amount of undiluted coolant I needed to add, so I tried draining some coolant and adding undiluted coolant to bring up the concentration. I need some of the tests strips that work with all glycols. I figure I should try to get the concentration above 50%.