It still should have oil pressure. Even if there was no return back to the block ,it should be pumping oil into the canister.Look deeper into the engine. Maybe oil galley plug is out. and Whats the engine?

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1936 1.5 wrecker,1937 gmc coe,1939 Chevrolet coe,1942 4x4 coe, 1942 coe,1946 dump,1947 2 ton dump,another 1947 2 ton dump,1950 coe,1967 c30,1937 cat 22,1936 Chevrolet 5 window foremans coupe, 1914 ford speedster.