Jere M.

Dropped off our 2020 GLS 580 to dealer service this morning (58,000 miles) , the car has been losing engine coolant. At first I'd have to fill up half a gallon every 5,000 miles or so, now it is going through that same amount in a quarter of that distance. No visible leaks, no coolant in the oil, no coolant smell in the exhaust.
They just called me saying someone filled up the washer reservoir with coolant, so my extended warranty will not cover it and they want $1100 to replace the windshield washer fluid system. I am very familiar with all things engine related, have replaced head gaskets myself etc. and assured her there is no way that happened. She said she would double check with tech and call me back.

I found a few threads on here saying the coolant circuit goes through the washer bottle to heat the windshield washer fluid. I called her back and asked for them to check this, waiting on call back from the tech. Find it very concerning that they came out of the gate accusing someone of filling up the washer reservoir with antifreeze when they should know about the coolant circuit going into the windshield washer reservoir.
It is also mildly concerning that I didn't notice that I was spraying antifreeze on my windshield for the last few MONTHS lol. Every time I used the washer fluid I was like WTF, these wipers must be SHOT!..Nope, it was ANTIFREEZE. Will follow up on how this gets resolved.

chassis

Heating circuit (coolant) into the washer bottle leaked. They are giving you BS. Read the fine print on the warranty document.