I actually put on my big girl pants & replaced the reservoir.. but what are those little mesh baskets? Haven't found any pics of them or references about them ANY WHERE!! though I have a really hard time finding anything about my 2014 gli, so not shocking, I guess.
Thank you, & yeah gunk is right! Ugh!
The coolant expansion tank contains a silicate repository. Silicate is used to protect the aluminum components in the coolant
system from corrosion. There are silicates in the G13 coolant, but they are used up over time if the engine is subject to high
To compensate for the silicate consumption, silicate is taken from the repository and added to the coolant. The silicate
repository provides additional protection against corrosion for the aluminum components in the coolant system over the entire
lifespan of the engine.