Gas fumes after fill up - part number help

[maverck]

Here are details:
-81 SC - 100k miles. Have owned for 3 years
-tank and fuel lines at tank replaced by PO
-all rubber lines replaced after I purchased the car as the were leaking.

I now get a fuel smell in the cabin after fill up. No noticeable leaks anywhere. After a bunch of searching I am fairly certain it is some of the breather / filler hoses in the trunk. Planning to replace all rubber hoses and the gas cap.

Does anyone have part number(s) for the hoses? Or should I simply replace some like the hoses to the evap tank with generic hoses?

TIA for any help!

[EC900]

Here a couple points from my experience-
Make sure there are a two lines leading from fuel tank and into the expansion tank which is tucked above of the washer fluid tank. One large hose is from tank the other smaller hose leads to charcoal canister. When these are not connected and hose left in trunk, gas odor will be present all the time. You’ll see the where hose attaches to the tub, they’re metal stubs.

As for the large filler hose, they tend to dry rot/crack, but that would be evident leakage. You can replace just the gas cap gasket. I’m not certain if the screw on, spring tensioned gas cap is actually vented. Generic replacement hose is fine so long as it’s fuel line not vacuum line.

Overfilling will result in a fuel odor, that hose is located at the filler tube the exposed hose runs down behind left fender wall, in the event of overfill the spillage drains towards the pavement - could it might just be lingering spillage odor….if that hose is missing you’d be dribbling spilled gas down the tire. Maybe even the gas fill level was too high and is sloshing to overfill?

[HarryD]

I used clear PVC hose from my local hardware store. It has been many years with no issues.

[maverck]

Originally Posted by EC900

Here a couple points from my experience-
Make sure there are a two lines leading from fuel tank and into the expansion tank which is tucked above of the washer fluid tank. One large hose is from tank the other smaller hose leads to charcoal canister. When these are not connected and hose left in trunk, gas odor will be present all the time. You’ll see the where hose attaches to the tub, they’re metal stubs.

As for the large filler hose, they tend to dry rot/crack, but that would be evident leakage. You can replace just the gas cap gasket. I’m not certain if the screw on, spring tensioned gas cap is actually vented. Generic replacement hose is fine so long as it’s fuel line not vacuum line.

Overfilling will result in a fuel odor, that hose is located at the filler tube the exposed hose runs down behind left fender wall, in the event of overfill the spillage drains towards the pavement - could it might just be lingering spillage odor….if that hose is missing you’d be dribbling spilled gas down the tire. Maybe even the gas fill level was too high and is sloshing to overfill?

Thanks for the tips!

[Missed Approach]

Hi maverck- Per your request for part numbers, see the image below for the SC tank ventilation system.



Additionally, here's my story on fuel line odor issues...

https://forums.pelicanparts.com/porsche-911-technical-forum/1043707-expansion-tank-fuel-smell-quandary.html

Hope this helps!

[Missed Approach]

Here's the filler neck exploded diagram as well...

[PeteKz]

Maverck: Very high probability that the expansion tank just ahead of the oil gauge has split a seam. That's what happened in my car, and the symptoms are exactly as you describe. It was a PITA to get out and required removing the driver's side hood hinge. I sealed it up with RTV silicone sealer and it has been holding up for two years so far.

[Bill Douglas]

Maybe replace the gas cap first. It's easiest.

I replaced the seal on my SC's cap and the smells went away.

[EC900]

This also reminds me that I once tried to find the source of a fuel leak after smelling gasoline in the cabin.
Turned out I apparently stepped into a puddle of gas at the pump left by a previous customer. Once it was on my shoe soles, the residual liquid transferred into the floor mat. Aired out in a day.

[maverck]

Originally Posted by Missed Approach

Here's the filler neck exploded diagram as well...

This is excellent! Thank you.

[Bob Kontak]

Gas cap first as Bill D mentioned.