quick question about the proper fill level for coolant on these vehicles. when cold, the coolant should come up to the bottom of the black section of the stick, correct? if so, how low does this seem in terms of quantity? I've been worried about head bolts and burning coolant, but no warning messages have come up yet. Also, haven't noticed any white smoke from the exhaust or any odd engine behavior. car has right about 69k on it now and I haven't been monitoring the coolant level regularly.

here's what the level looks like from the side

Looks like your coolant is down a little. I would fill it to the level indicator in the first picture. When full the level should be even with the split in the expansion tank. You only look to be down a few ounces, maybe a cup and probably nothing to worry about. Get you dealer to top it off for you or buy a jug of MB Coolant and mix it 50/50 with distilled water. Monitor from there.

I'll keep an eye on it from now on. Thanks for the info and tip.

okay. so just got back from a ~800 mile road trip and this morning and the level is lower than it was last week (based on a marking I made on the outside of the reservoir). any idea how low the level needs to get before it trips the warning message indicator on the dash? reason being, I don't want to top it off if the car is eating coolant.

You shouldn't be using ANY coolant. It's not like oil. Stop driving the car and bring it to someone to diagnose. Hoping for the best.

Did you find any problem with the car?