Overheating and questions thermal sensors

Since that oil cooler looks like it is aluminum, I'm thinking any kind of lye-based cleaner is a no-go as it will attack the aluminum. Likewise I have motor-aid and a heat exchanger in the house for house heat from the engine - I don't know if any of those components are aluminum or not.

I'm going to let this Red Devil flush do its thing for a week but I'm betting it's not going to work.

Steve