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Gas tank vent line?


Rjsantos592
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I have a 64 Buick Skylark, vent line follows supply line which goes to engine compartment and stops. Sometimes gas spews out. Can I rectify by installing a vapor canister?  Or is there another problem that needs to be addressed?

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Read the factory service manual. It's not a vent line, it's a fuel return line. Cars that were expected to see higher underhood temperatures (typically cars with A/C or high performance engines) used a fuel pump that recirculated a small amount of the fuel back to the tank. This helped lower fuel temperatures and mitigated percolation and vapor lock. Apparently someone installed an incorrect fuel pump without the return line and just left that hose open. I'd worry about the quality of any other work done to the car previously as well. The vent is at the tank, in the form of a vented gas cap and vent lines that run up in the rear axle cavity. Vapor canisters weren't required by the EPA until the 1970 model year. This is what the correct fuel pump looks like. Note the additional hose barb for the return line. Also  note that most catalog listings do not show this for the early 300 motors. Don't rely on them to be accurate. Carter M4512 or Airtex 40515 will work.

 

40515-1__ra_p.jpg

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1 hour ago, EmTee said:

In some cases the return line attached to a second (smaller) output at the fuel filter.

 

318enVkNS5L._AC_.jpg

 

Good call, that's actually what the 64 Skylarks with fuel return used. Hastings GF19. Thanks!

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