[H_T]

2021 m550; Had a coolant flush about 2500 miles ago (around 25k miles). The warning did NOT come on. However, I’ve noticed I had to add in coolant between service every once in awhile (oil changes every 5k).

The small turbo tank was still full. Had to add 1 full red party cup of HT-12 coolant w/ distilled 50/50 mix (I think these cups measure slightly above a measuring cup).

I did not see any leaks or white spots, but the cap was extremely hard to take off as usual. Used some of the distilled water on a paper towel to clean of the cap and slot, which made it much easier to screw on.

Will check in at 30k miles to see if have add another cup before servicing.