Re: What is this?
It's not a catch can. It is plumbed into the intake portion of the manifold. You fill the container with diesel fuel additive thru the large silver knob and adjust the flow rate with the spring loaded needle valve located at the left of the container breather. The breather allows clean air into the additive resivior so the bottle won't collapse. The additive flows thru the copper line into the intake stream to clean /lube upper intake components. Additives similar to Stanadyne diesel performance formula. Hope this helps.
"Mean Green" '10 Army green 4x4 AT ATRAC/rear locker. Demello 3 hoop w\BD sqd, Smittybilt M1 Gen2, PURE FJ sliders, EXPO-1 Wash Bottle, Ironman FCP C-springs front, Boss 2.5 w/ TOYTEC superflex rear, SPC DOM LCA. 16" BF 285 KO2's E-rated.
"Angry Orange" '13 Magma 4x4 AT ATRAC/rear locker, CRAWL. Demello 3 hoop Evil Eye w\BD sqd, Smittybilt M1 Gen2, AllPro sliders, EXPO-1 Wash Bottle, Ironman FCP-B front, 5100 w/ TOYTEC superflex rear. SPC DOM LCA's, 17" BF AT's C-rated.