I ended up running an errand today that took me past the MB dealer. I bought 1 meter of 3.5 mm ID vacuum hose, and 1 meter of 5 mm ID hose. Part numbers are:

617-997-08-82 for the 3.5 mm ID hose.

605-078-05-81 for the 5 mm ID hose.

I've had enough with the other misc hardware store hose. I've used all different types and materials and invariably, it becomes brittle and cracks in under a year. I just want something that I can install and forget about for a few years at least. Of course the dealer prices on this were astronomical, $15.44 for 1m of 3.5mm hose and $21.00 for 1m of 5mm hose. But hopefully now I won't get P0200 every other month because some random hose segment cracked apart AGAIN...

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'98 E300 turbodiesel