All the literature is on JST's side with the regular flush. My data point of one doesn't prove anything, it just affects me emotionally (and it also means very likely no more subie boxers for life). I actually did some reading on flushes and plan on getting on one in my next service.

The coolant reservoir kept taking more and more water to the point that I think I added more than a quart. I haven't started the car yet, it has a very narrow window from Min to Max and I have a feeling this will make the warning go away. I think I had been below min for some time but the warning light takes a lot lower level to trigger.

So OCD me is not upset that I weakened the coolant 50:50 too much, but then again the car takes a massive 6 gallons of it! I don't think I'll be going through next winter with this coolant anyway.

Hopefully it was just a slow evaporation that happened to go past the warning trigger and it's not a leak. Not looking forward to dropping car off at indie shops 45min away with rides needed both ways and 4-figure bills.

I had the same issue on my 987. I ended up topping it off with regular old tap water. :eek:

Fortunately, the entire system ended up getting drained and re-filled when the dealer performed the warranty HPFP replacement :lol:

I checked my records, no flushes under my ownership. However, carfax shows that when the car was about 1yr/5k miles old, it got a new water pump and hence coolant flush at the dealer. So the coolant in it is from 2014. In the first year I had it, I kept an eye on it, kept making sure it was above minimum and when I complained, I got a new coolant cap (still under warranty).

Since then, so we're talking since 2016-2017 or so, I have not been checking, just waiting for the idiot light to go on. It seemed to much trouble to keep it just above the 'min' mark. Min to max seems really close, I wonder how much capacity there is between the 'yellow' warning and the minimum. From the looks of it at least a quart, we'll see.