Nothing goes there.... it is just a vent for the atmospheric pressure device attached to the IP....(It got me also when I got my first Benz).......I wanted to plug something on to it.....but did not know what...Cheers!

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1978 Yellow 300D (The Mustard Toad)
1980 Blue 240D (The Iron Toad)
1989 Grey Mitsu.4WD Mighty Max Pickup (Needs a Diesel transplant bad)

(Open the pod bay doors HAL)