Alright, just bought my 90 Civic Wagon, as some of you know. I pulled the gas cap and it was hard as heck to get off, and when it came loose it made a "shhhhh" sound for about 10 seconds. I know this means that the gas tank is builing pressure. Anyways, it's in the old gas cap thats not venting, and it's made wierd so I can't get a replacement.

My question is, is there a way to drill holes in it to make it vent? If I drill straight into it, it will get water in it, and thats not good. So does anyone have any ideas? Maybe drill holes into the sides of it?

 

Your gas cap is not suppose to vent, the gas caps that vent have been illegal for many years. The EVAP system is suppose to remove the fuel vapors that build up in the gas tank. So maybe have the EVAP system checked. If you have any more questions, jus ask.

 

Most cars (at least all of the ones I have ever driven) make that sound when removing the gas cap. It is supposed to be that way. If you drill holes in your gas cap, you will almost surely get a Check Engine Light.

 

Didn't know that. None of my other cars do it. Where is the EVAP system located?

 

I have three Honda's and they all do it... more noticeable at lower fuel levels... Well I have 4 but the motorcycle doesn't count...

 

The EVAP system has a bunch of parts, but it prolly isn't your problem. Usually you will get a code if your EVAP system is bad. I think that all cars make that sound.

 

DOn't drill hole, it's normal and good, if it's vent or loss tight like my after-market one, the Check Engine Light will be on, dealer will only check it for $85, fix from $200 to $3000, they don't even tell me to re-tight the dame gas cap!, So it took me a week to found out what caused it, since it's after-market for Civic, it requires many more clicked than the stock one in order to be tight!