QUOTING: BDAqua "I think you can use regulat Anti-Freeze/water mixture."
Nope. The regular EG coolant will have issues with the residue of the old harsh saline coolant that was originally used.
Your only hope is Sierra Propylene Glycol that has the required corrosion inhibitors and using Distilled Water.
Being that the LCS is a mixed metal loop, the ratio of the coolant is 66%PG and 33%DW. Or 2/3rd to 1/3rd mixture.
QUOTING: Heikki Lindholm "According to the MSDS the Delphi A2 coolant in the OP's Quad is 80% DI water 15% propylene glycol. That doesn't sound very harsh."
My reference is with the A1 coolant, the first type used. That was the harsh coolant.
QUOTING: Ramón G Castañeda "What's the remaining 5% ?"
The remaining 5% is more proprietary corrosion inhibitors for the A2 coolant. Thus, my remarks to use the Sierra PG at 33% to 66% DI or DW or RO if neither can be had. You have no idea what the other inhibitors actually are nor where to obtain them.
If a rebuilt loop uses 80% DW with 15% PG, they will indeed run into trouble. The second gen-LCS micro-channels will gunk up in time with corrosion. This is the reason when some of the threads here are talking about water-blocks having a higher heat load vs. the other one in the loop. In some cases up to 50%. The Sierra PG coolant had been tested extensively in the G5 LCS development and proven to be a good solution.