Real noob question, you will laugh haha - But I have no clue and I have to ask

So I got a gas can like this. Now my question is the small yellow cap at the back. Is that supposed to be on tight so it seals. So if I blow in the front no air should be escaping from the back cap? Is that just a hole to open when you pour gas so it doesn’t glug glug? I thought that was the point of the special self venting spout…

It’s called a vent cap.

You open it when you pour gas out of the can.


You’d think that self-venting design for the spout would eliminate the need for another vent. But it appears from the photo the self venting design is geared more for lower flow rate pouring; if you were trying to pour gas as fast as possible the space around the outlet might all get filled with liquid gasoline and the self-venting spout idea wouldn’t work.

You can buy those little plastic caps on ebay. I have added them to all my plastic cas cans because all the self venting spouts don’t work wort a hoot. You just drill a 1/2 " hole with a spade bit and pop them in.

You use the self-venting nozzle when filling things like lawn mowers, snow throwers, etc…

But if you use the gas can to add gas to a modern vehicle gas tank, the ORVR system won’t allow the gas can to vent properly. So you open the vent cap.

It’s an EPA thing.


Ok thanks guys :slightly_smiling_face:

So keep it shut tight when it’s in storage so no water get in the ethanol mix?



Always add a fuel stabilizer such as Sta-Bil when storing gasoline.


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It’s only going to maximum 1 month maybe. It’s E85 so it’s even less store able right?

Would you recommend it’s for 1 month?

What do you have that can use E85 . I know your BMW can’t . I certainly would not put it in lawnmower.


Are you planning to use that E85 gas in a flex-fuel vehicle?


It’s to run E fuel mix maps on my car.

E85 is rare in Canada. This “local” sports club 40 mins away sell some. I only plan to use it at drag days at my local track so having a 20 litre few weeks before for when I go will give me a full tank of E30 mix when mixed properly.

Yes it can.

Alcohol drag racing?

You’re good to go.

The gas can will work.


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Alcohol lasts a mighty long time.


Yeah but I’ve been told E85 has a tedency to absob water, kinda like brake fluid.

So the container has to be saeled really really well.