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tucsonjwt · 10-13-2016, 11:08 AM

I am not sure about your setup, but I have an 83 C20 which came from the factory with 3 nipple sending units. 3/4 ton trucks were considered heavy duty in 1983 and did not need an evap canister. The third nipple on my truck has a short piece of fuel hose capped by a one way plastic valve (same as the one on the differential vent.) I extended the vent hoses on the dual tanks to terminate just in front of the rear bumper and installed valves there. This keeps the fuel odor away from the cab but you can smell it when you are at the back of the truck.

10-13-2016, 11:08 AM	#2
tucsonjwt Registered User Join Date: Jul 2007 Location: Tucson, AZ Posts: 3,188	Re: Is my gas tank vent sufficient? I am not sure about your setup, but I have an 83 C20 which came from the factory with 3 nipple sending units. 3/4 ton trucks were considered heavy duty in 1983 and did not need an evap canister. The third nipple on my truck has a short piece of fuel hose capped by a one way plastic valve (same as the one on the differential vent.) I extended the vent hoses on the dual tanks to terminate just in front of the rear bumper and installed valves there. This keeps the fuel odor away from the cab but you can smell it when you are at the back of the truck.