Conference vmsnet::car$note:carbuffs

    I filled up my GAS TANK (<--note connection to topic) this morning on
    the way to work.  The particular station I go to has an annoying
    feature in that once you're finished pumping the gas and replace the
    hose the pay at the pump prompter asks you if you want to buy a car
    wash and you've got to push the yes or no key to get your recipt
    printed.
    On impulse, I elected to get my car washed in the station's brushless
    car wash bay.
    Here's my question: As the machine was making its second pass, I heard
    a "thunk" which ;announced that the stream of water had closed nozzle
    cover.  I looked out the side view mirror to see my gas cap hanging
    out, suspended by its retainer. 
    After I drove out of the bay, I got out to check things out -- and
    screw in the gas cap.  Visual inspection showed about 1-2 tablespoons
    of water at the top of the filler, blocked by the spring-loaded
    thingee.  I took a paper towel and removed it before securing the cap.
    
    So, should I worry a lot about the amount of water that might have been
    introduced into the 13.2 gallons of gas I had just added?  Is there
    something (e.g., "dry gas") I should add as a preventive measure?
    
    Thanks

I would put in a bottle of gas line antifreeze in the tank and immediately
fill it up with gas.  Do the same thing on the next two tankfulls of
gas.  If you can't find gas line antifreeze in your area, use a bottle of
fuel injection cleaner instead.  It's very important to absorb what water
did make it into your tank before it rusts the tank or the fuel injectors.
My guess is that less than a cup made it into the tank.  

Jim

    
    	Yeah, the flapper isn't a water-tight mechanism, so some did get
    	in there.  Like Jim said, not alot ... but it could be enough to
    	cause problems.
    

Add a bottle of gas line antifreeze and go for a very long drive. The water
will settle to the bottom of the tank where the fuel pickup is. 

The gasline antifreeze will absorb water making it less likely to pool
in larger quantites in the tank. Little by little, the water will go
through the system and exit the exhaust as steam.

Get the tank as empty as you dare before the next fillup and then fill 
it to the brim.

But mostly, don't worry about it. 

Doug.

    We have all heard about how explosive a few little gasoline fumes 
    can be.  Tuesday night, I accidently conducted my own experement to
    prove it.  I bought a new tank for my GTO, which did not come with a
    filler neck.  The neck is soldered into the tank, so it must be removed
    from the old tank with a torch and transfered to the new one.  I
    completely drained all liquid from the tank, and let in sit outside
    opened up for two days.  Then I filled it completely with water to
    displace the fumes, and drained it.  I took the torch and heated up the
    filler neck.  Just as the solder softened and I began to bull the neck
    from the tank, something ignited.  It let out a boom like a small
    firecracker, the next think I knew all the skin was blown off of the
    back of my hand and part of my wrist.  The tank, which used to be flat,
    is now almost round, and I have second degree burns.  I'll be OK, but
    it scares the hell out of me to think about it.  I just wanted to place
    this here as a warning to anyone working with a gas tank.  I thought I
    had done all the right things, and I still had a nasty accident.  
    
    Dave

    
    	Yup, gas does not dissolve in water.....
    
    	Years ago, I worked for a guy that would weld tanks.  We did mostly
    VW stuff, and at that time (approx 1971...) bugs would rust at the very
    bottom of the tank.
    
    	We did the very same procedure, even to the point of pulling the 
    gas guage, putting a hose into the filler neck, and would let it
    'flush' for up to an hour.  The very FIRST thing he would do, is stick
    the torch (acetylene) right into the tank to ignite the remaining
    fumes.  Of course everyone within sight would start to run when he did
    this (he loved drama).  The fumes would ignite, sometimes soft,
    sometimes hard, depended how long we had flushed it.  After that, it
    was 'safe'.  He'd weld it, and reinstall.
    
    	The best one was when he did a gremlin (?) tank, which was quite
    a bit larger than a vw tank.  He 'underestimated' the flush time.  When
    he 'lit' the tank, because there was only the filler hole, the damn
    thing ignited, the flash all came out the filler neck, the tank then
    became a loose jet engine and flew across the garage.  AWESOME!!!!!!
    But we knew he was crazy anyway.  Once we had finally hammered the tank
    enough to get it back into the car, the owner was extra pleased, as he
    had picked up a gallon or two of 'extra' tank capacity.....
    
    	The 'physics' of volatile fumes is quite interesting to say the
    least....   8*)))
    
    	Glad you're still with us, and thanks for the warning.....
    
    		glen(n)

For what its worth when my father-in-law was just a young lad he use to work 
as a body man in Canada.  He met this old timer that would weld gas tanks.
To do it he would run a hose from the exhast of a running car to the gas 
tank and let if fill with exhaust fumes.  While keeping the car running he
could weld no problem.  He would even put the lit torch in side the tank and
no problem.  Have no idea why it worked.

I have never seen this done nor do I suggest that anyone try it but figured
I would share this.

Wayne

    re: .53
    
    A guess at the principle, nothing more...
    
    Exhaust fumes contain carbon monoxide.  By filling the tank with carbon
    monoxide and continuing to do so, any straight oxygen that enters the
    tank will combine with the carbon monoxide and make carbon dioxide.
    
    Without oxygen, there is nothing to react with the fuel to create the
    combustion reaction under heat.
    
    This is just a guess.  Kids, don't try this at home...
    
    -- Russ

    
    	I've seen it done, and it does work.
    
    	At least, the tank didn't explode in this particular instance.  I
    	wouldn't bet my last dollar that it will always work perfectly.
    

    	re:51 and others
    
    	Would it be possible to just leave the water in the tank to a point
    below the filler neck, or would that prevent the solder from being able
    to melt ?
    
    	Ray

    
    Any water vapour around and you will have great difficulty
    forming a metallurgical bond (weld, solder etc.)
    
    /Pat

    Re: .53

    I worked my way through school as a mechanic for the owner/proprietor
    of a local garage.  He not only did automotive repair, but was also a 
    crackerjack welder -- stainless, aluminum, u-name-it, he had quite a
    reputation for being able to braze/arc/MIG just about anything to 
    anything.  

    Sure enough, he'd weld gas tanks, and after flushing the tank w/water 
    he'd use the exhaust from a running car in order to provide an
    oxygen-depleted environment inside the tank which allowed him to
    safely proceed with the repair effort.  Note that this was in the '79-'81
    timeframe, and the reason why I add this is that the new (at the time)
    A.I.R. (air injection reactor) pumps on the newer autos concerned him;
    after a near miss involving some ominous rumblings from a tank he was
    welding, he sussed the problem back to the AIR pump-equipped car he
    was using.  Afterwards, he always insisted on an older, non-AIR-pump-
    equipped vehicle to supply a 'proper' exhaust.  

    Funny how things change.  When I was young and immortal getting paid 
    4 bux/hr to work for a true motorhead was icing on the cake...
    now you couldn't pay me enuf money to be in the same room as someone
    welding on a gas tank.  ;-)
               

    
    The way the big guys do this when removing underground gas tanks is to
    drain the tank, then fill it with dry ice until the fog comes out the
    top. Then you can use a backhoe if you want and not worry about
    gouging it. FWIW.
    
    Same theory as car exhaust to displace the O2.
    

Using exhaust fumes isn't all that reliable unless you're absolutely certain 
the vehicle is running right.  Normally an idling engine will tend to run a 
tad rich  i.e. you are pumping combustible fumes into the fuel tank.

Fill the tank with Halon or carbontetrachloride if you can find either.

Otherwise, wash the tank out with a soapy water solution  (Squirt a 
teaspoon of dishwashing liquid in the tank then fill it with water.  Slosh 
it around good and dump it out)

Rinse the tank then fill it with water.

Touch a flame to the filler neck and burn off the remaining fumes.  It'll 
be like lighting the burner on your gas stove.  No explosion or anything 
like that.  In fact, if you did the job right in the first place there 
won't be any fumes left to burn.

The larger the air volume, the greater the explosion.  Keep the air volume 
small and you'll get a slight poof if there are any fumes left to burn.

We used to, on a VERY REGULAR BASIS, light off FULL gas tanks in the bone 
yard I hung around at in the 50s and early 60s.  Fill the tank, touch a 
match to the filler neck and let it burn for hours.  That's what we used to 
set the pile of wrecks on fire to get rid of all the interior and crap so 
that all we had left was crushable metal.

Anyway....

Drain the tank a bit or simply re-position it so that the part to be welded 
is above the water level and have at it.  Keeping as much water in it as 
possible reduces the volume of air inside.  (peace of mind)

I did a Morris Minor tank in March down in Melbourne (Australia) like that 
and I didn't get ANY flame out of the tank when I passed the acetylene 
torch over the filler neck.

    
>We used to, on a VERY REGULAR BASIS, light off FULL gas tanks in the bone 
>yard I hung around at in the 50s and early 60s.  Fill the tank, touch a 
>match to the filler neck and let it burn for hours.  That's what we used to 
>set the pile of wrecks on fire to get rid of all the interior and crap so 
>that all we had left was crushable metal.
    
    	Reminds me of the story about the gas station attendant who was
    	asked to put out his cigarette when pumping gas, so he extinguished
    	it with a squirt of gas from the pump.
    

    
    
    	Must've been the guy that used to pump gas in my home town. It WAS
    a bit unnerving...:)
    
    

Yea, it ain't the gasoline that ignites, it's the fumes and they're heavier 
than air.  Squirt a cig with an open nozzle and the liquid'll suffocate the 
cig.

    Well, my new tank is installed, and my hand is healing better than
    expected.  Even though I was working with a clean, brand new tank, I
    still got the shakes when I first went near it with the torch to solder
    in the filler neck.  I think if I ever need to change a tank again, I
    will pay sombody to remove the neck.
    
    Dave

On newer chevy/gmc truck the fuel filter is in the frame rail about mid point
down the chassis. 

When I was changing mine, gas (standing in about 16 feet of tubing) ran down my
arms, my clothes, my garage floor, etc.. I remember thinking "WHAT AM I F%#KING
NUTS?!! ALL THIS TO SAVE $40 BUCKS TO HAVE SOMEONE ELSE RISK GOING UP IN A BALL
OF FLAME?" 

Next time, I'll pay someone. At least on carb models, the filter was in the carb
and when you disconnected it you got maybe 3 tablespoons of fuel on the intake
and a few drops on the wrench. With the new design there is no pitcock for and
aft of the filter. Basically you are bleeding about two pints of fuel onto
yourself. Unless you put your full body under the vehicle inside of the body
(not where I wanted to be in case something happened). Not again.

roger.

 

    been there, done that, said the same thing you did.
    
    You can either:  Undo the filter with a rag in your hand to soak
    up all the spilage or...
    
    pull the fuse for the fuel pump and run the thing out of gas.
    
    MadMike

    PPS:  ANYTIME I work with fuel I like to do it OUTSIDE my garage.
    One time I was trying to fire up my Z in the garage after changing the
    carb and fuel lines and I was pissing 108 octane gas all over the place
    like it was coming out of a super-soaker deal.  I'm sitting in the
    thing hearing WWWaaaaWaaaaaWWWWaaaaaa from the starter and WWHIRRRRRRRR
    from the fuel pump and a big splashing noise - along with the DISTINCT
    sweet smell of fuel.  Yumm yumm... I IMMEDIATELY STOPPED and had to
    air out both bays of my garage and listen to my wife bitch a while,
    since our bedroom is right above the garage.  Ya, she'da bitched if
    the thing started too: But that's her problem. :^)
    
    MadMike

Many moons ago, my neighbor was replacing his fuel filter and in the
middle of the process he found he had the wrong part. He hopped into his
other car left to get a replacement. He put the hood down but not shut 
on the now disassembled beast before he left.

He was thankful that he was doing the work outside since, while he 
was gone, his wife decided to go do some shopping. She tried to start the
car which resulted in fuel spillage all over the engine followed by an
impressive fire.

Doug.

    That's one good reason to disconnect the battery negative cable even
    when you don't think you NEED to disconnect it.. 
    
    ...tom