W114

I have a 1975 300D it is very difficult to start and when I do get it to start there is a load clacking noise that doesn't change when engine is idle or at higher RPM's.

can anyone explain why my 73 280 s has an rpm flare or hesitation going into 2nd gear?

Need help with a 75 240D heater. I have not worked on one of these before, so I am not sure even how the controls work. The fan in this car only comes on when I rotate the AC knob. The fan does not have high speed which I assume is just a blower resistor. Shouldnt the fan come on with just the defrost knob? There is one other knob below, I guessed it was the dash dimmer. I get no heat at all. Heater valves work Ok and Heater cores are getting flow. Anyone have a wiring diagram& vacuum diagram for the heater system on this car. The one book i do have shows 300 heater systems but leaves this one out. Thanks in advance for any help