Gas tank capacity

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JayDubya
I am merely driving my van
I am merely driving my van
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Joined: Sat Mar 06, 2010 9:49 am

Gas tank capacity

Post by JayDubya »

Hi guys, new member here. I have a '99 conversion, and I am surprised at how much I enjoy driving the thing.
Looking through the Haynes manual, I see that the tank capacity for '98 through '00 is 25 gallons, and the capacity for several years before and after those years is 27 gallons. Does anyone know why?
1999 Mark III butcher job with the rare 4.3 V-6 engine

astroturf
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Re: Gas tank capacity

Post by astroturf »

JayDubya wrote:Hi guys, new member here. I have a '99 conversion, and I am surprised at how much I enjoy driving the thing.
Looking through the Haynes manual, I see that the tank capacity for '98 through '00 is 25 gallons, and the capacity for several years before and after those years is 27 gallons. Does anyone know why?
I really don't have an answer. But, I have a thought. My 05 is spec'd with a 27 gallon tank. I've never been able to put more than 22 gallons in it. Gauge reflects empty at that point. That being said, I don't think it's a good idea to run all of the gas out, Because the touchy and difficult to replace fuel pumps use the fuel in the tank for cooling. Jim
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Smiliesafari
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Re: Gas tank capacity

Post by Smiliesafari »

Welcome to the site, Jay. My 96 SLX Safari is rated at 27 but the most I'v been able to put in it is 24. And that is when I ran out of gas and and was lucky enough to coast into a gas station. I think the engineers use a mathematical formula to determine capacity instead of actually measuring.
1996 Safari SLX Hotair balloon transport vehicle
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remark123
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Re: Gas tank capacity

Post by remark123 »

Smiles,
you couldn't be more correct! One of the biggest discussions we ever got into when we worked at GM was how the devil do you figure out the capacity of a tank! Gas is a relative volume, its density changes with the temperature, humidity, etc. I suspect that 5 different vans with the same tank would actually end up with 5 different capacities! This is the reason why the standard disclaimer in the owner's manual about ..."actual results may vary". It also reminds me of the comment cards we used to get at Wentzville when we began to offer the outside temperature display on the ATC HVAC units. The Plant manager and I used to laugh at the comments of "my thermometer says that it is 85 degrees outside and the thermometer on the bank sign that I just drove by said 84"! The reason that the capacity was increased was that the customer base uttered enough complaints that the engineers listened. That, and the dies for the tank needed to be replaced anyhoo... :-$
1991 Hartland EXT with Z motor. Only 190K miles on mostly original parts.

Topic author
JayDubya
I am merely driving my van
I am merely driving my van
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Joined: Sat Mar 06, 2010 9:49 am

Re: Gas tank capacity

Post by JayDubya »

Interesting. So we are not even sure if there was actually any difference between the 25 & the 27 gallon tanks, eh? Who'da thunk it?
I was hoping that someone could tell me if the earlier or later (27 gal) tank would fit my '99.
1999 Mark III butcher job with the rare 4.3 V-6 engine

6spd_monte
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Re: Gas tank capacity

Post by 6spd_monte »

My tank is rated at 27 gallons and I actually put 25.5 in it once, but the needle had been pointing to empty on the gauge for quite a while. It probably indicates empty a bit before the tank actually is empty.
-James

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kings-x59
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Re: Gas tank capacity

Post by kings-x59 »

as the summer gas prices peak, it will be holding a capacity known as "freaking expensive" :yikes:
'89 Astro, 4.3L, TBI. Minor intake and exhaust mods. Rebuilt 700R4 trans (by me). Corvette servo, 0.5" boost valve, police grade 1-2 accumulator spring (shifts fast and solid). B&M stacked plate trans cooler. Bilstein shocks. Belltech sway bars front and back. New head unit, speakers and subwoofer. Needs paint and a new headliner.

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Cobraearl
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Re: Gas tank capacity

Post by Cobraearl »

IF ive run out of gas 10 times in my 62 years, 7 have been in my 1999 ASTO. The Gauge LIES. The Miles left in the tank meter LIES.. Mine will hold 24 gallons ABSOULUTELY OUT OF GAS.

I use the Odometer to keep up with when I should refill. if its past 300 miles I fill up. BUT, if im towing something like my boat or my larger landscape trailer, I need to find gas sooner.

That being said, I like the vehicle............. I JUST WISH i could trust the gauges. ANY EASY SOLUTIONS for making the gauges a bit more ACCURATE??????????????

earl
1999 Astro, 7 passenger,
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ihatemybike
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Re: Gas tank capacity

Post by ihatemybike »

I usually fill when the gauge says between 1/8 and 1/4. After a few tanks to get calibrated, my ScanGauge is pretty accurate. Green I can go about 520 miles and put shy of 24 gallons in. Grumpy is on it's first full tank in a while, looks to be good for 480 miles though.
Aaron

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