Distilled water and Redline Water Wetter. RMI to clean out the crusties.
Bo, I do not want to step on your toes, but Red Line is not a complete additive for radiators as it a primarily a surficant to reduce surface tension between the water and the metal to transfer heat. It will erode the solder in the radiator unless another additive is used. Not an opinion, but actual from experience.
RMI is a complete package for protection, keeping the system clean, and it also contains a surificant, so Red Line is not needed.
RMI is the only complete radiator additive for protection, and will balance PH in the system to prevent electrolysis and corrosion, and it is also the only additive that will clean the cooling system w/o acidic or caustic elements.
In the early 90's I dealt with the owner of RMI, and also visited with Red Line owners who were originally with RMI and started their own company.
RMI back then had no presence in the speciality world, so it was a pleasure to work with them as their first distributor.
The new owner of RMI is a great guy, and owns a GN!