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Gas tank sending unit??

Discussion in 'Chevy Trucks' started by Zooman, Sep 15, 2001.

  1. Zooman

    Zooman Junior Member
    Messages: 7

    On my gas tank sending unit there are three fittings on top. two of them go to my fuel pump and the last one just has a little piece of rubber gas line on it. I think that the last one must have gone to the evaporator cannister at some time. It is long gone now.
    Can I just block this off? I don't want to get water or anything im my tank. My truck has a 80 cab on it.
    1978 Chev 3/4
  2. Chuck Smith

    Chuck Smith 2000 Club Member
    from NJ
    Messages: 2,317

    You can't block it off. It is the only vent for the fuel tank. You can extend it further if you want, with a longer hose. On the HD Emissions models, and pre-smog trucks, that is the same vent set up they used. In the end of the hose, you put a vent cap. The same type that is used on your front and rear axle vent hoses, and transfer case vent hose. It is a plastic fitting, with a loose cap on it.

    You can see one here:

  3. Zooman

    Zooman Junior Member
    Messages: 7

    Thanks Chuck
    Thats what I wasn't sure about.
  4. raceman6135

    raceman6135 Member
    Messages: 61

    Just as a side note.... that's the same vent they use on Turbo 350 transmissions, in case you ever need to replace one.