Vapour return line explanation.

[64riviera]

Can someone tell me why there's a vapor return line on myriviera.

What's the function and how does it work?

It seems to me that it is only on cars equipped with AC. What has the AC to dowith it?

What would happen if I would block this line?

Tried to figure it out myself by just think logically. Didn’t work (thefiguring out I mean )

Never thought a simple line could raise so many questions.

[RivNut]

From what I've been led to understand it is there to help prevent vapor lock on the fuel line for a hot engine. Apparently the a/c cars would get much hotter than the non a/c cars therefore a/c cars are the only ones that required it. Anyone else?

Ed

[Jim Cannon]

Ed's explanation is correct. The underhood temperatures on A/C equipped cars got high enough for the fuel to boil in the fuel line in the summer, in stop and go traffic. This return line from the fuel filter sends the vapor back to the tank to condense into a liquid. Otherwise it would go to the carb as vapor and make the engine run poorly or die.

You can decide what the consequences would be to you if you plugged it.