can you elaborate on the vac flap?

side note, when I did the glow plugs I had to pull the intake. I cleaned about 5 pounds of sludge out of it, but I neglected to do the same to the egr valve

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'92 300D 2.5
'99 E300TD

When an EGR valve plugs itself, it's a blessing.
No more exhaust enters the intake.
No more sludge build up.

Garsh, some peoples help the EGR block itself faster using a shim of metal.
Just sayin'

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Cheers!
Scott McPhee

1987 300D