Charcoal Canister Seal
 

Getting the Gross Leak OBD Code.
found that I am missing the rubber seal/grommet where the Purge Valve goes into the Vapor canister.

Outside of buying a new canister, is there anything I can do/use to remedy this?

Thanks

Possibly go to a junkyard and take a seal of an HHR, cobalt or cruze. Maybe all gm cars have this seal also.
Or PM hellshotrod on this forum.

unfortunately, not having any junkyard luck with this.

Oh, yes. This was my issue. My Vapor Canister Vent Valve failed last summer. Easy 10 minute fix. Bought a new one. Got the gross leak P0455 code. I thought it was because I bought the "Standard" brand name instead of AC Delco. Months later I found a rubber O ring on the garage floor. Never put 2 and 2 together. Threw the O ring away. Then I finally got around to troubleshooting that code. I took out the Vapor Canister Vent Valve and realized I was I was an idiot. Of course you can't buy that seal if your life depended on it.

So here's what I did last fall. A heater hose is about the right size to go around the tube. But it's too thick to fit into the canister opening. So I cut a thin slice of the hose, like an olive slice, and used black electrical tape to secure it. I positioned it so that it pushed up against the Vapor Canister. That got rid of the Gross Leak. Then I got a Small Leak code P0442. I was at least making progress. I left it alone for the winter. When all is said and done these two codes don't really affect the car. They are just annoying.

March came and I had to fix it for emissions testing and plate renewal. I decided to seal the edge with a little bead of silicone. It worked great. No more code. Passed emissions.

Doc brown
Won't the heater hose be affected from gas fumes ?

It's been on there since October. I took it off to try another Vent Valve thinking that a new Delco one might come with that O ring. But it looked jut fine. What I thought might break down was the black tape. It was fine and the glue on the tape was good as new. I don't think there is much vapor going through there. If you follow the tube up from the Vent Valve it's an open end next to your filler tube. You don't see it because of the plastic cover around the filler tube. If there was that much vapor going through they would not leave it open ended.

On my Sierra that tube wraps around the top of the transmission and hangs off the right side with a small foam filter on the end. And I think that's only there to prevent dirt from going in the tube.

That's because the vent "gulps" air. The purge valve sucks vapor. Thus the names "vent" and "purge"

I strongly suggest, replace the part and oring or just buy the oring only. Your favourite parts palace should be able to match up those for you.

I actually solved it with dipstick tube grommet.
It was just about the same size. Had to cut off a tiny bit.
Pit it on and my cel went off by itself!

Great fixed.

Dipstick grommet from what year car/transmission ?

So this code has 0 to do with smog or how the car runs or anything like that? I thought this had something to do with the massive cloud of smoke from the exhaust or the foul odor inside the car which smells like foul exhaust.

What code? Evap?
This post is old.

P0455 - large evap leak.

I've got a few things going on with the car but it sounds like it doesn't really relate to exhaust clouds or smog?

I'm not an expert so just trying to figure it out....

It does have to do with emissions. The fuel vapor type, not exhaust gases. And it does affect the efficiency of the engine.

If the purge valve is the leak it will not idle right. Especially after fueling up.
What are your symptoms?

other than the code and "check gas cap" message on DIC, foul exhaust odor, cloud of smoke from exhaust after 3k rpm pull...however does not smoke at all on the freeway...

You have just the one code for large evap leak? That is not causing the smoke under load. Are you consuming oil? Does the car accelerate OK?
The smell could be from the EVAP.

The VENT valve might cause problems while filling the fuel tank.
The Purge valve has nothing to do with a vacuum leak and nothing to do with idling after a fill up event. It might cause a hard start and/or P0171/P0172.
Exhaust fumes in the cabin is not a minor problem, things like death could result.
I don't know which basket case hhrumadbruh is talking about, so I don't know it talking about the flex pipe is warranted.

There are a few jury rigs mentioned, in this very thread even!

Yeah that and a knock sensor code.

tiny oil dripping from bottom of the car but oil level in the dipstick is good.

slow coolant level drop. Once a week I need to top off the reservoir.

trace amount of oily residue on top of coolant in fill cap.

Car will sputter, act as if it's going to stall out, rpm fluctuates if given a minimal amount of pedal but will act fine if given over 1500 rpm.

Yeah, the evap leak probably isn't causing all your other problems but you already know that. What other codes besides P0455?