Let me make a point here most Mercedes produced from 92-late 95 had engine wiring harness problems, the electronic accelerator on most 119,104 and even some 202 have bad harness' also . That 400e has a hose that goes from p/s pump to the resevoir , that is what leaks most of the time. As for timing chains on these motors I have only done a few and that is at 150k-200k miles . Never seen one of these jump timing either , let me take that back , only one and that was from improper maintenance . The 400e is a beautifull well running machine when properly taken care of . The distributor caps and rotors yopu should change at 100k if they havent been done yet. Mercedes are hard on secondary ignition components. As for the evaporator , well they all go bad just dont go back with factory.
We install the all alluminum one and we never had any noise like some predict. Good luck and look at it real close.