The overflow valve you have operates on a different principle than the original 2-piece valve did. The old-style valves had a spring and a ball inside and kept a constant pressure in the fuel system. The new-style valves have a drilled orifice and a weak spring holding closed a non-return valve. The orifice is smaller to provide restriction. Either valve should work if your lift pump is in healthy shape. The new-style valve showed up with the M pump and was standard equipment on the OM60x series engines.

If you have air in the system, find the leak, likely your primer handle if its the old style. The OFV won't have anything to do with air in the system. Since there isn't a ball bearing chattering in the new style OFV, you won't hear it "squeak" when priming.

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]