As I stated earlier today, I did test the gas cap with my mouth and it appears to work at the moment, but I'll keep an eye on it.

So I checked all the hoses to the canister and I was able to push air through all of them and get a response from my wife as to whether she heard air rushing or not and they are all clear.

I then put it all back together and I am getting a nice vacuum at the hose that goes back to the tank so I'm going to go with the fact that the valve in the canister at least works.

I'll continue to monitor this and see how it acts at the next fill up. If still the same I will swap out the gas cap and then go from there, hopefully I can report back by the end of the week that all is well in the world, so stay posted.

Matt
--
1989 - 245, 1990 - 245, 1991 - 245, and 1993 - 245

Hi,

What is considered normal is to have the gas to make no discernible noise or if you do hear anything it will be a slight pressure release sound.
The cap is meant to trap gas vapors in the tank and its evaporative emission control system. As mention the canister is up under the front bumper drivers side.

There is a check valve on the canister operated by manifold vacuum under certain manifold vacuum conditions. If that is working it should under most conditions keep the fuel tank very low on pressure.
During hot days or excessive agitation of the fuel (low on fuel) there can be times that the canister does not keep up with.
This is when you might hear a eek-sound to almost a chirp.
This is the gas cap leaking off down to a preset pressure.
The gas cap also lets air in so a vacuum is not created and this works both ways when changing altitudes, like traveling through a mountain range.

So, an occasional pressure release is very normal.
I think it maybe mentioned in the owners manual or has been stressed by Volvo service bulletins.
In fact, if it didn't do it occasionally, it might mean that the outer split rubber o ring or the caps check valve inside maybe leaking.

I suck and blow on the cap to make sure it holds but let air in!
I can't get it to pressurize high enough to to make it release. So, it must be a few psi or more.
The outer ring is a visual thing, looking, for cracks or listening for that pressure noise.

Phil

Next time you take it for VEIP they'll put your cap on their tester, note that it fails, but maybe not say anything, because it doesn't keep you from passing the emissions overall.

"MVA VEIP - Gas Cap Leak Check. In addition to the emissions test all vehicles also receive an advisory gas cap leak test.
The cap is placed on a testing adapter and gently pressurized with air to ensure that it seals tightly. While the results of this part of the test currently will not cause your vehicle to fail the emissions test, a gas cap that fails should be replaced in order to reduce gasoline vapor loss. Gasoline vapor loss contributes to our current pollution problem, and can also decrease your fuel efficiency."
--
Art Benstein near Baltimore

"You can say any foolish thing to a dog, and the dog will give you a look that says, ''My God, you're right! I never would've thought of that!'" (Dave Barry)