Moaning/whistling sound from gas filler compartment

[fredpayne]

I have a Moaning/whistling sound coming from the gas filler compartment, I have no clue what it is, has anybody heard of this? I have a 2003 Boxster S

Thanks

[CenterIsl]

I had the same problem, and a quick search of the forum turned up others with the problem saying it was the vent tube. I don't understand the exact details, but for some it was a fuel filling switch inside the neck that fails, leaving the vent tube open during operation (normally it's cut off). They fixed the switch / valve (I think some called it the "carbon control valve") and it went away, or they stuffed something in the tube to alter the noise.

Well, my car (also a 2003 S) had the same symptoms, and blocking the vent hole when not filling did reduce the sound somewhat. But my mechanic found that the tube was misrouted and being pinched - when he fixed _that_ the sound went away almost completely. I say almost completely, because I've discovered that it does come back periodically, and I think it has something to do with the fuel filler cap not being _completely_ tight. When I give that another turn past the ratchet, it seems to go away completely.

[fredpayne]

Thanks, I will try some of these things, The Porsche Dealer here said it was a valve housing P/N 996 201 231 01 and they wanted 561.00 to replace it.

I will sure try some of your suggestions first.

[fredpayne]

You are the second person tell me it might be a fuel filler cap.

[fredpayne]

After Boardwalk quoted me 561.00 to fix this problem, I purchased a 6.99 gas cap at auto zone, problem fixed.

[Allen K. Littlefield]

Originally Posted by fredpayne

After Boardwalk quoted me 561.00 to fix this problem, I purchased a 6.99 gas cap at auto zone, problem fixed.

So that is where the noise is coming from on my '02 2.7! Mine seems to only happen when car is slightly turning right. I thought that the tire rotating in this position somehow vented air across an 'undisclosed' opening and set off the sound, not unlike blowing over the top of an empty bottle but a little higher pitched. I will look into the cheap solutions and thanks to you all.

AKL

[CenterIsl]

I'm kinda embarassed about this, but figured I should add to the thread for posterity...

When I read about the vent hole originally, I opened the filler flap and there it was, right under the cap. That's the hole I was taping - with inconclusive results.

But this weekend I noticed that there's another grommeted hole at the leading edge of the filler compartment - on the other side of the hinge point! It's kinda awkward to put an easily removed piece of tape over that hole because the leading edge of the flap goes past it, but doing that completely cured my howl.

Just another sad case of "Using The Wrong Hole"!

[fredpayne]

Don't feel bad, I think we've all used the wrong hole at one time or another.

[fredpayne]

Just an FYI my whistling is back, I guess I will have to go ahead and get it repaired, the Porsche Dealer told me it wouldn't hurt anything, but the noise is driving me nuts. I'm attaching a file showing the part that needs replaced.