Slow coolant lose since appx. 5th or 4th year of car age.
Does the pattern described below matches common experiences regarding symptoms of coolant losses?
BMW with B48 252 PS (built somewhen between late 2015 and early 2018) loses slowly coolant. So far no leakage spot found. Current diagnosis measure is the use of liquid detector die Brilliant Coolant available on european online retailers. A number of short-distance drives were accomplished with detector die put to cooling circuit. I can inspect engine bay using only infrared lamp (no special glasses available). So far got informed about BMW common weakness regarding coolant robber houses and observed micro-perforations of the hose connecting coolant reservoir with engine head. Following those hints I inspected that area using IR lamp and see spurious traces in area that I judge to be engine suspension below one such hose. Residuals look like pollen particles distributed slightly on upper surface of engine suspension more than continues tracks of dried fluid.
It is hard to document with camera what I see during inspecting the depths of engine bay.