My 81 300SD dose't have anything between the intake manifold and the ALDA. Is it supposed to be like this? Or did the PO remove the valve? The line connecting to the ALDA is in 3 segments, connected by rubber hose, which I replaced with extra vacuum line fittings from removing the lines to my EGR, since they were super loose and leaking badly. Should I go to the junk yard later and pull a switchover valve and install it? OR does this car originally not have one? I'm worried about blowing my motor after reading this, http://www.dieselgiant.com/mercedesaldaboostsystemservi.htm.

It should have this:

http://mb.braingears.com/126_DISC1/program/Engine/617/07_1-015.pdf