the power steering cooling line connects to the rubber power steering hose attached by a clip I believe to the sheet metal behind the various pulleys and serp belt on the driver's side of the engine. You can follow the rigid line backwards if you look carefully. Not sure of part number though.

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87 300e (white/black; amg body kit)
88 300ce (red/cream; amg body kit)
93 300ce cabrio (white/blue/blue top)
93 300ce cabrio (black/grey/black top)
98 ml 320 (totaled @ 137,000 miles)
99 clk320 (black/grey/black top)