I find that I need to add a little coolant into my 2008 RX350 now at 45,000 miles, but the dealer wants $35 for a 1 gallon jug of pre-mixed! I really only need maybe 1 quart or less, as sometimes the coolant is over the LOW line while other times, the tank is totally empty.
I note that I have leftover specialty coolant from other cars, in particular orange GM Dex-Cool and pink Audi/VW G12. I know I can just add distilled water, though the 50/50 factory mix would be diluted, but I'm also wondering how different the recommended Toyota Super Long Life Coolant is to the Audi/VW G12 (Pentosin). Both are even pink! (though color alone probably is not a good enough indicator).
The owner's manual says, " “Toyota Super Long Life Coolant” or similar high quality ethylene glycol based non-silicate, non-amine, non-nitrite and non-borate coolant with long-life hybrid organic acid technology." Both therefore are probably compatible. Still, I'd like any thoughts before I do something to a good running car that I might regret later...
CP