macaddict111

Hey guys! Have a 2017 TTS with 4000 miles on it. The coolant level is at (maybe 1 mm below) the "Min" line on the bottle when cold. Is this a cause for concern? Maybe some manufacturing air bubbles worked their way out?

Huey52

Possibly just settling post manufacturing. Of course you should top up to at least the minimum line when cold (see my present level photo). I use 50/50 pre-mixed Prestone but have not had to add any to my 2016, now at 10k miles; not sure if any was added at 5k service however.

Or if a purist (requires mixing, preferably with distilled water) - https://www.ecstuning.com/b-genuine-...iABEgJJsvD_BwE

macaddict111

Update: I recently brought my TTS in for steering error messages, and brought up the fact it was still losing coolant. They did an overnight pressure test, and found a "category III coolant leak" (I'm guessing means very minor). They weren't able to conclude on a location, but the service advisor went ahead and ordered a replacement of the engine-mounted thermostat, which is apparently very prone to leaks (as I've seen on the forums). The one they put on is two revisions newer, so I'm hoping that will solve the issue permanently.

ourlee