yes the unit needs to be broken down to the smallest bits - purge cleaning the evaporator is a chore on the W124 as its hidden behind the dashboard, but a smart technician can clean it out by removing the expansion valve that is next to the brake booster.

the high pressure can also be extra oil in the system.

Your tech sounds he did correct - one cannot assume a part is good or bad unless the system is run under full load in correct circumstances (full clean charge).

btw - dont overlook the cabin filters too, they are under the wiper cowling on this car and are 90% of the time overlooked because it was only the last 2 years of the W124 that had those.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)