JUst A Few Small Jobs 

Thank you. The Great Smokey Mountains sounds amazing, ride safe and enjoy your trip.

'One of those job things' 😂😂

I'd imagine it's an anti freeze mix, which contains inhibitors to stop galvanic reaction

For galvanic corrosion to occur the two metals need to be connected electrically, i.e. in contact with each other for the galvanic cell to be completed. They are not in the case as the silicone hose is non conducive. Also the copper (cathode) surface area is tiny in comparison to radiators and cylinder block aluminium (anode) which would be the sacrificial so would have minimal effect. Also coolant is normally mixed using distilled water to prevent limescale forming in the cooling system so the coolant is almost non conducive

Thank you. Yes I will add some caps, its hard to get some designs to work well on caps but I think the latest one will be fine so I will get it sorted.