[Peter Z]

Hey guys, I just got my first bmw last month it a 2019 bmw m850xi convertible and been driving 4000+miles on it, currently is 42666 miles
just like last saturday when I got inside my car and I got coolant warning through the Id7 system, I check both tank and turns out it the big one for engine was running out of the coolant, and the cap plastic part got thermal cracking due to high temperatures from N63tu3 engine. And some small plastic pieces get into the tank, I just put distilled water in it, and drive it for two days right now no more coolant code came back. I just got the new cap from dealer and waiting tomorrow morning can put it in.
But there's couple things making me worried:
1. Yesterday after 40 min driving I have the yellow sign of engine is hot need cooldown notification. And it gone after I shut the engine down for a while, there's no alert came back.
2. Today after I drive for 1 hour and shut it for 5 min when I start again, the rpm when start the car is not stable for just a sec and the car sounds weak. But still be able to drive and no code in it.

I already on fixing an old audi before this bmw got the coolant problem, it make me nervous and I hope it not a big problem I need to worry about.

[Dr Thrillride]

Hi Peter, search this forum in advanced mode for ‘coolant’ and ‘reservoir’. Your reservoir may be leaking and may wreak havoc with your coils. There’s a good aftermarket replacement part from RK Autowerkes or there’s supposedly a new part from BMW. I can’t speak for M850 though