jpilk99

I am just about to install the new fuel tank I got for my 98. I had to use a tank for a 1969 Chevy Caprice as it was the only one that came close to the original dimensions of the rotted one I took off the car. The old tank had 3 vent pipes and the new one only 1. Am I screwed? I thought I might just get use connectors and get all 3 vent lines into 1 and connect that to the vent pipe on the tank.... Thoughts? Here's a picture of the ..."stand pipe" above the rear axle with all vent hoses sitting next to each other, and the old fuel lines that were rotted and news once installed.

Thank you.

Jay

Olds64

Connect the 3 vents on the chassis to the tank like you were thinking. Your charcoal canister also needs to be in the loop. Do you have the 72 FSM & CSM? It will let you know how it was originally setup.

cdrod

These are the connections to the emissions stand pipe, usually located behind the back seat. This was an early emissions system to capture fuel vapors; prior to 1972 most cars simply vented them to the atmosphere. The lone pipe exiting the standpipe should go forward to the engine compartment and be connect to a vapor canister filled with charcoal. This canister is also connected to ported carb vacuum which pulls fuel vapors from the tank into the engine to be burned. The outer 2 pipes in the group of three are vent intakes from the gas tank to the standpipe. The stand pipe allows the fuel vapors to condense back to liquid form, the middle hose returns the liquid fuel back to the tank.

I've attached a pdf sketch of the hose routing for a '72 Cutlass/442.

Rodney

Olds64

Rodney, thanks for posting the schematic.👍

jpilk99

Thank you. I do have the CSM and will make sure charcoal canister is correctly looped. A 'muscle car' friend said it was no big deal to do the 3-into-1 for the vents into the tank - I just wanted to confirm!!!! Thanks again.