Gasoline is a material with density and vapor pressure characteristics that let it travel a fair distance from the source, and mix readily with air. If the concentration in air is above 1.4%, or below 7.6%, it is explosivly flammable. 1 gallon of spilled gasoline can produce an explosive mix equivalent to over 500 gallons volume (Think of 10 of those 55 gallon oil drums). More probable than an explosion, however, is a very rapid and hot fire.

All the scary stuff said, chances are pretty low that it is going to explode or ignite from your engine. More likely to go off from the engine of the guy waiting in line behind you to use the pump - his engine is usually closer to your gas tank than your engine, and he/she usually doesn't shut off while waiting! However, as Clint Eastwood said, "Do you feel lucky?". You are betting that random chance will not create an explosive mix of air and gasoline, and will not provide a spark. Extremely unlikely events for random chance to reproduce?

Our emergency room once had a patient who was cleaning parts in a pan containing about a pint of gasoline. It was a nice, hot, dry day. He dropped his wrench onto the concrete floor while he was putting a part into the pan. WHOOSH! No more eyebrows or lashes, and an instant blistered and bright red face! Luckily he was not inhaling at the time the mix went off, or ditto conditions to his throat and lungs!

Extremely unlikely does NOT mean the same thing as impossible. Always cut the cards!

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JCE
87 300E, 65k miles
Smoke Silver

[This message has been edited by JCE (edited 11-15-2000).]

Funny it's against the law to have your car running whille refueling. BUT, in NYC the Poice Dept. Guidelines for the Police are, DO NOT shut the car off while refueling. Go figure. Are they trying to tell them something.

I'm siding with trent and G-Man,

The risk factor is a non-issue, with thousands of fill-ups a day across this nation * 15 years and only 1 incident? Better to do what you want.

Besides, the colder the outside temp is, the more comfortable the interior is with the engine running and the heater on and music. Besides, I'm usually sitting IN my car during the refueling, in comfort.

Thats what the spring loaded lever clip is for!

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Ross
96 C280, Greenish Black

This subject is a HOT one!! Good start...
Let's hope the big brothers from NHSTA or other agencies are not reading this and try to pass a regulation of having ignition interlocks on our gas flaps!! Who's watching over you now syndrome again...my 2cents...

Tobias MB
4 MB's

Good point. That would be another device we would have to override.
Big brother would really hate my radar jamming system. That is if I had one (or two) which of course I don't. No really I don't. Because that may be illegal. Just like speeding, which I never do. No really I don't. Because there is a chance that may be dangerous. I am sure there is a study somewhere that could confirm that. Oh yeah, now I remember. That study was in the same journal as the "Don't fuel up with the engine running" study.

Let the mayhem begin.....

Maybe I got in the habit of shutting it off to fuel it in the sixties. My hot rods of that era were so fuel hungry, that the only way I could top off the tank was to shut it off while fueling or it would burn the gas faster than I could pump it in. Good thing gas was $.23 per gallon.

I want to make it clear that I don't think that shutting off the engine should be the law either. I just don't see the point in burning fuel for nothing. How much trouble can it be to turn off the engine, then restart it when you're ready to go. Maybe a chauffer is the answer.



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Larry Bible
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

Gotta ahnd it to ya Larry, I really enjoy your posts.
I also have experience with the big inch "muscle" engines and their desire to suck fuel as fast as you can pump it. I once had a Chevy 454 that if you fueled up with the engine running, it would try to suck the fuel nozzle and hose right into the tank through the filler neck. Talk about thirsty. I used to joke that when I would put my foot into it and open up the secondaries on the carb that I needed a friend to sit in the engine bay with a can and pour gasoline directly into the carb just to keep up.
I really don't care if people turn off the car or not when fueling up, just pay attention to what is going on. Don't leave kids in the car who could throw it into gear, and don't leave it unlocked. You may never see it again. Stuff like that. And make sure the hose is out of the filler tube before you drive away.

Happy trails.

trent,

There's a little bit of good in everything. The good thing about those muscle cars was that you never needed to put a tachometer in them. All you had to do was just shift every 1/4 tank of loss on the fuel guage.

Have a great day,

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Larry Bible
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

One of the other good things (and most memorable) was the sound of a nice true dual exhaust on those big V-8's. I would drive with the windows down just to hear those puppies play their tune. Sweet music to my ears.

Not like nowadays when I hear these guys in a 4 banger rice rocket with some sort of glasspack or straight pipe or whatever (?). There were times when I thought that either some very angry locusts were invading the street, or that some of these cars are actually powered by large honeybees.

trent,

You are so right. I remember in the sixties, many people had pretty loud exhausts, most of them were glasspacks and factory manifolds. But I could hear a loud car go by and tell you what make it was without seeing it. They all had a different sound, mostly determined by firing order.

I always thought that the Chryslers sounded the best. But I long for the days of hearing those engines. They were definitely music.

The glasspacks sounded great, but we found out later that they didn't flow near as well as the turbo type mufflers and some of the others such as the Chrysler Hemi mufflers. This was too bad as far as the music went, because the glasspacks sounded great.

The music was great, but I don't long for the point ignitions, two brush generators and drum brakes.

Have a great day,

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Larry Bible
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

The only real problem with leaving your car running while refueling is the darn OBD light....or "check engine" light will illuminate on the dash of the newer MB's....because the system checks reveal a pressure loss.

Interesting, my '99 CLK doesn't do that.
Of course with all of the other little things that are out of whack on this car, I am not surprised.

IF YOU LIKE TO WRITE THE SEQUEL TO MURPHYS LAW YOU COULD HAVE A GOOD SCRIPT IN YOUR HANDS / IF IT CAN GO WRONG ...

Considering all I have read on this great thread I too believe there is very little chance of ignition at the pumps. Consider that the fumes are heavier than air and will lay at the bottom of a chamber, a boat bilge, for instance. If left with no room to escape, or a bilge blower, to blow them out into the atmosphere, they pose a significant threat and will easily combust if ignited. That's why inboard marine gas engines are required to have blowers to reduce this significant hazard. The nature of cars obviously does not require a blower so unless our line leaks fumes into the trunk we are probably pretty safe. I also leave the engine running frequently at the pump, especially if I started the engine only a few minutes earlier on a cold morning.

I was under the impression this would make the "Check Engine" light illuminate indicating a pressure leak in the gas tank. Is that not true??

Thanks



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Dean

90' 300CE
80' 300D
80' 300SD