My convertible‘s cooling system had been subjected to some deferred maintenance before I bought the car. I drained the coolant and got plenty of orange with it, too. So, I rinsed it with water. Filled the system with water. Ran the engine and more orange. So, I pulled the block drains, etc, etc. Same thing over and over after rinsing and running at least 6 or 7 times. Still got orange water churning up as soon as I started the engine. My friend suggested Thermocure. I followed the instructions and after going through the process the cooling system has been clean and rust-free! I found mine at Walmart (pained me to go I there as I ABSOLUTELY HATE Walmart but it was for the betterment of a 409). I highly recommend it and would definitely buy it again. Around $25, if I remember correctly.
https://evapo-rust.com/thermocure/
Ross
https://evapo-rust.com/thermocure/
Ross