Hello all, new to this forum. Busy with full mechanical re-build of a 66 W108 250S. Great hobby car, as it is an early W108 so mechanically like a Fintail and as such you can do most work on it yourself. However it still has that class and "jewel like" quiality Mercedes cars are famous for! Recently de-rusted my exhaust manifolds in some fermented Molasses. Yes, if you've never tried this, you won't believe how well it works! They are now painted with high heat paint and look good. The only cloud on the horizon is these strange "valves" in the manifolds. Very little mention of them in the books I have. They seem to provide some warming of the inlet manifold, probably in very cold Wx conditions, at start up, then open when the engine gets warm? The point is I'm very keen to restore this car as original as possible, so would like to restore this system. However, the spindles the "butterfly" like valves sit on are frozen solid in the manifolds. some gentle persuasion with heat and copper mallet has not worked. Don't want to damage /crack the manifolds! Luckily they are frozen in the open position. So my question is:
What is their function exactly?
Wil the car be effected when they don't work? (I've come across cars in South Africa, which seem to be unaffected by them not working?)
Can you get spare parts to re-build them?

Any views/experiences will be appreciated. Will try post some photos when I can sort out how to!