that one port is blocked, are you referring to one nipple/port having a cap over it? If so, I believe mine ('87 300TD) did. Though I do not remember the procedure exactly, I think what I was instructed to do was apply vac to each port checking for leakage. Somewhere in my cranial cavity I seem to remember a warning about not getting too carried away with the amount of vac though I am possibly getting two routines mixed up. Larry Bible was the source for my testing procedure . . .

What are you attempting to accomplish/solve?
Steve

__________________
Steve
'87 300TD - 132K - Soon 4-Sale
'84 300D Turbo - 122K - Driving
'77 VW Type II - 77K - Restored
'08 250EX Ninja
English Bulldog (Brier) - My best friend. Passed away 12/02/04 while in my arms.