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!tom · Posted: Mon Mar 26, 2012 5:12 pm Post subject: Smelly gas tank

Well, the transmission is out, so I figured I'd take a peek at why I always smell gas if I fill the tank up all the way.

Out comes the tank, and I'm expecting to find the standard crack. Click for bigger pics.

Hmmm. Doesn't look like what I'd expect if it were cracked.

Maybe this is the problem?

Looks okay around the sender.

And nothing exciting along the front edge either.

So, what is the wisdom of the group?

Obviously I'm going to replace the lines. I'll give it a good looking at for cracks too. What's your advice?

Edit: Fixed links
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78 924 NA
5-lug

staticsan · Joined: 19 Jan 2009 Posts: 450 Location: Sydney, Australia

What do you define as "all the way"? I found that if I keep filling after the first click, it fills the filler tube. That's probably not a good thing and may be producing the fumes.

Wade.

!tom · Posted: Tue Mar 27, 2012 12:29 am Post subject:

All the way means letting the gas pump stop filling. I never bother spending 10 minutes trying to put another $0.53 worth of fuel in like I see lots of people doing. In my other vehicles, I squeeze the trigger 'till the gas stops, then I'm done.
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78 924 NA
5-lug

Ian89C4 · Joined: 01 Apr 2011 Posts: 561 Location: North Carolina

Perhaps aging vent lines that come out of the tank and loop underneath the plastic cover that is inside the cabin. I know when I pulled the the plastic cover off there was a very strong smell of fuel.
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Ian Edgerly
North Carolina

Current:
1981 924 SCCA/ChampCar Weissach Race Car ("Serenity")
1987 924S ChampCar Endurance Car ("Der Weg")
1980 924 Euro ("Wahala")

Ozzie · Posted: Tue Mar 27, 2012 8:37 am Post subject:

Change all your fuel line around the tank.
They could be cracked and you would never know.
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Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

!tom · Posted: Fri Mar 30, 2012 4:00 pm Post subject:

I was hoping for advice on the vent valve.

In the oft-referenced Pelican thread on cracked tanks, the following is shown as the likely culprit:

My '78 has the following arrangement (as usual, click if you want it bigger):

Should I be replacing this valve as is suggested in the Pelican thread to prevent my tank from cracking?

I suspect mine hasn't cracked either because this valve is different than the later models used, or because my hose rotted out years ago and won't hold a vacuum, preventing the flexing that is presumed to cause the cracks.

Thoughts?

Edit: Fixed links
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78 924 NA
5-lug

!tom · Posted: Sat Mar 31, 2012 9:36 am Post subject:

Has anyone else experimented with different valves here?
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78 924 NA
5-lug

gerben1986 · Joined: 13 Mar 2008 Posts: 232 Location: The Netherlands

Interesting thread. A week ago I mentioned fuel beneath the car after a fillup. But it came from the upside of the thank on the passangersside.

musicalannette · Joined: 21 Feb 2012 Posts: 413 Location: UK

I must admit, I don't normally get a petrol smell (happened the odd time when i filled up), but when i remove the rear seats to make way for an l.p.g. kit, it sounds good advice to have look. Do you know if the later models suffer the same?
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I KNEW white wall tyres were invented by Americans .....just not at Boeing.... to be fitted on the 737.....

!tom · Posted: Tue Apr 24, 2012 2:34 pm Post subject:

Well, I got the gas tank back in yesterday.

I replaced all the lines connecting to the tank. In doing so, I removed and re-installed the existing valve.

When it was off, I tested it by blowing through it, and found that it seems to be a one-way valve. If it indeed has a calibrated leak in it, it's very slow, and undetectable by my uncalibrated breath.

Is there some type of pressure release mechanism on the early gas caps?
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78 924 NA
5-lug

!tom · Posted: Tue Feb 19, 2013 4:52 pm Post subject:

ARGH!

Gassed up today to the very top. Then, there was a steady stream of gas pouring out of the right rear of the car!

I did a pressure test on my tank by putting 1 or 2 PSI in it, and hosing the outside with soapy water when it was out last year.

The only leak I saw was around the sender gasket. I wasn't too worried as there wasn't any fuel stains there at the time, as you can see by the pictures above.

I hope that's all the problem is now. With gas in the filler neck, there will be positive pressure in the tank trying to push fuel past that gasket. Normally when fuel is drawn from the tank, a slight vacuum should help that gasket seal better.

What's the wisdom of the group?

What's that gasket like, and should I try to buy one, or just make one?
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78 924 NA
5-lug

!tom · Posted: Wed Feb 20, 2013 5:15 pm Post subject:

Nuts!

It doesn't look like the sender gasket, as it isn't wet around there.
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78 924 NA
5-lug

!tom · Posted: Wed May 29, 2013 1:41 pm Post subject:

Well, it happened again today.

I gassed up, and then parked on a slant with the fuel filler side of the car on the low side.

I came back to the car and there was a puddle of gasoline under the car!

I lifted up the carpet in the back, popped off the cover over the sender, and saw gasoline pooled on top of the tank right there.

Pretty scary!

Anyway, I need to replace that gasket. Problem is, I'm a tad bit confused by what I found in the PET.

Anybody know what the part number is, or where I can get one? Or, do I need more than one?

Pellican Parts suggests:
477-919-133-M260
but I'm not sure if that's the correct part.

Help!

Thanks!
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78 924 NA
5-lug

!tom · Posted: Sat Jun 01, 2013 12:37 pm Post subject:

Wow! Nobody has ever needed to replace a fuel sender gasket before. Impressive!
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78 924 NA
5-lug

staticsan · Joined: 19 Jan 2009 Posts: 450 Location: Sydney, Australia

I replaced the sender gasket when I cleaned the sender ages ago. I think I bought mine from Automotion.

Wade.
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'82 British NA - Which I think I've been very lucky with!