I’ve used it on my 2001 Blazer, with cast iron block and head 4.3 vortec.
The truck has over 110k miles, and I did the Thermocure Evaporust flush about a year ago I think. The reason I used Thermocure was because the previous owner didn’t change out the Dexcool coolant on time, and it turned into sludge and caused some bad rusting inside the system. I have flushed the system once about 2 years ago, and the rust problem returned because I didn’t remove the rust inside with just a regular flush.
I just drained all the rusty coolant, then filled the system with Thermocure and distilled water and drove it for 3 days. And this is what I drained out of the system:
View attachment 308417
As you can see, it is completely black, only after 3 days of daily driving it with nothing but Thermocure and distilled water in the system. I’d say it was about a 30/70 mix of Thermocure/water.
After this, I filled and drained the system probably 8-10 times a went through 12+ gallons of distilled water until it drained completely clear with no visible debris.
Then I filled the system with pre-diluted prestone Maxlife coolant. And the coolant inside the overflow tank and radiator still looks like brand new clean coolant a year later.
I have not experienced any problems with Thermocure, but I know it works like no other. It’s really effective, and I recommend Thermocure on cast iron engines that have bad rust in the cooling system.
But I would only use it on systems that have really bad rusting and scaling from people using tap water or bad coolant in an iron block system. If your system is dirty, but you don’t see rust on the inside of the cooling jackets, you probably don’t need to use Thermocure.
