Zerex sells a "phosphate free" coolant that is approved for plastic, and aluminum.. It's PH balanced, and priced slightly higher that their standard product..
If my MB is so friggin' finiky that it's gonna need a special this, and a special that everytime it needs service... Perhaps I'll go back to Buick.. I hope that a standard DOT 4 synthetic brake fluid was OK???
89 300SEL Money Pit
92 Blown Buick Ultra Pimpmobile 220K and adding 1K per week
88 Wagoneer Slightly modified (Not for soccer moms)
04 Kia Sedona with every option... NICE