If your only problem with the heater is that you can't get hot air from the center vents then you're SOL. The ACC system of your car is designed to not let heated air flow through the center vents. I won't talk about this anymore because it's a sore point with me. Part of the reason I got the S420 is because MB C O R R E C T E D this P R O B L E M in later cars.

The basic test of the clutch fan is like this. Get the engine over 100*C if you can then shut off the engine. Spin the clutch fan. If it spins freely, the clutch mechanism isn't working. If it advances a blade or two then very likely it's working. The exact engagement temperature of the clutch is in the archives. That would be the temperature at the clutch, not what's displayed in teh temp gauge.

The elctric fan should come on at low speed when the coolant gets to 105*C and at high speed when the AC compressor is engaged and pumping refrigerant. To be clear, 100*C under load is not a problem. 100*C while idling or relaxed cruising is.

It is a timing chain. I don't know why I said timing belt. I haven't had a car with a timing belt in over 5 years. Not that it means anything

The rack damper is a bolt with a spring loaded pin inside it. It bolts to the back of the injection pump. Look for a 10mm head bolt held by a nut that takes a 13mm wrench. The procedure to adjust the rack damper is in the archives. You might want to give adustment a try before you replace the rack damper. From what I hear the silver color ones have weak springs and don't last as long as the gold color ones.

A great source of parts is a click away through the FastLane button at the top of this page. No one will take care of you like Phil will and you'll be helping the economy that keeps this website going. BTW, FastLane calls the rack damper as governor idler adj. pin. Woah! They were under $50 a couple of years ago.

Pacific Fuel Injection in SSF is a good place. I hear good things about Coast(?) Fuel Injection in San Jose but Pacific is almost exclusively a Bosch shop.

Sixto
95 S420
87 300SDL