Vintage Cars: 1976 Mercedes 450SL, radiator cap, fan clutch


Question
My car engine temp is around 200 degrees. we have changed water pump, flushed out radiator,changed radiator cap and installed a new thermostat. i thought maybe the head gasket, but oil is clean. Also, We integrated the auxiliary fan in the front to come on earlier to cool quicker.  Any ideas? Donna

Answer
sounds like the radiator is clogged , even with a flush these ol gals still have narrowing of the passages with time., may need to recore , or remove for acid flush.  How many miles on the car?

however

your fan clutch is working ??

You may have a bad temp sender ?

make sure of the following - correct temp thermostat put in with bleed hole ( arrow ) up
No air in the system ?  Park car so the nose is up run it , then let it sit ( kinda like burping the car)
Right radiator BAR pressure cap?

DO you have heat?  Heater core could be culprit
Let me know how else I can help , and please if you have time provide feedback on my response

Happy motoring
Ron