939 fuel tank capacity

[mikey]

Any chance the M931A2 has two 50g tanks and not 65g like the TM says?

I just filled an empty tank and it took 45 gallons. I know the fuel gauges aren't reliable, but that's off by a lot. Also I average 6.5mpg when I've been told I should get close to 10. If the tanks were 50g, it would be closer to 10mpg.

Thanks

Mikey

 

[ke5eua]

How did you verify it was empty?

Never trust a military fuel gauge. I changed both my sending units on my 818 but still carry a home depot paint stick to verify.

 

[mikey]

I was just trusting the gauge. This is the first time I've filled up an "empty" tank since I got the truck. I usually just throw $50 in when it hits 1/4. Perhaps when it hit's empty next time, I'll drain what's left and then fill it to see how much it takes.

 

[ke5eua]

Get a paint stick and when your gauge shows 1/2 see where the level is, and the same for 1/4.

 

[mikey]

You can't fit anything but a straw in a 939 tank. The fuel sieve is not removable and has holes about 1/8th of an inch.

 

[ke5eua]

You can't fit anything but a straw in a 939 tank. The fuel sieve is not removable and has holes about 1/8th of an inch.

The strainer is removable, use to pull mine all the time when filling up in Iraq.

 

[mikey]

Really? Never tried to yank it out, but it seems to be on there pretty good. Thanks for the info.

 

[ke5eua]

Yeah they tend to stick if never messed with. Forewarning, you will smell like diesel when done messing with it so you might want to wear some gloves, especially if the fuel is in the strainer.

TM extract.

View attachment fuel tank 939.pdf

 

[1 Patriot-of-many]

You can't fit anything but a straw in a 939 tank. The fuel sieve is not removable and has holes about 1/8th of an inch.

Grab the wider part of the base with a pipe wrench, it unscrews from the tank with the strainer.

 

[wreckerman893]

I was just trusting the gauge.

The only thing that lies more consistently than a career politician is a military vehicle fuel gauge.

You can't fit anything but a straw in a 939 tank. The fuel sieve is not removable and has holes about 1/8th of an inch.

I just knocked the bottom of the strainer out of mine with a Tanker Bar.

 

[wheelspinner]

WM why knock it out? It removes very easily, and then the cap goes back on in its place.

 

[plode]

WM why knock it out? It removes very easily, and then the cap goes back on in its place.

Come remove the one on my truck if it comes out so easy
I've tried for over an hour to get mine out...it doesn't budge.

 

[goldneagle]

Come remove the one on my truck if it comes out so easy
I've tried for over an hour to get mine out...it doesn't budge.

Try a bigger pipe wrench. Where in South Jersey do you live? I lived in Cherry Hill most of my life.

 

[Scar59]

Really? Never tried to yank it out, but it seems to be on there pretty good. Thanks for the info.

I have had several strainer assemblies that were installed with joint/pipe compound to ensure an air tight seal, a little heat from a propane torch will soften it up. I said a little heat.. keep the filler cap installed and get it real warm, not cherry red. If the paint is bubbling off and smoking, its to hot. A good strap wrench will work also.

 

[M813rc]

The military fuel gauges are virtually useless.

The way I check my mileage is to fill a tank to a certain mark (in the case of my 931's, its marked on the fuel strainer itself). Drive wherever it is you are driving to/from, then refill to exactly that mark again and calculate against the miles driven (determined by your GPS, or odometer you have checked for accuracy).

Also, when calculating range, remember that not all the fuel in the tank is usable. Some bigger truck tanks can have several gallons left when the pickup stops sending fuel down the line.

Cheers

 

[doghead]

Are you leaving room for fuel expansion?

Your fuel tank should have a tag welded on it that says it's capacity.

 

[jw4x4]

I removed both of my strainers with a vise-grip chain wrench. Far better option than the pipe wrench. The strainers are a PITA when fueling. They make fuel splash all over the place. I purchased locking fuel caps from an SS vendor and I love them.

 

[rory1919]

I was searching all over for a second tank when I picked up my truck last week. Fuel was all the way up the the strainer and the gauge said I had a half tank. I'm new to this too so I had no idea all the fuel gauges were so unreliable. Looks like there is no reason for me to change it out now.

Ill just oust keep it full all of the time.

 

[ke5eua]

I was searching all over for a second tank when I picked up my truck last week. Fuel was all the way up the the strainer and the gauge said I had a half tank. I'm new to this too so I had no idea all the fuel gauges were so unreliable. Looks like there is no reason for me to change it out now.

Ill just oust keep it full all of the time.

Most of the time it's a grounding issue or as in my case it was grounding and the sending units were rusty.

 

[plode]

Try a bigger pipe wrench. Where in South Jersey do you live? I lived in Cherry Hill most of my life.

Cape May County. My dad grew up in Cherry Hill...Grand parents used to live on Munn Ave.

Going to try a strap wrench...not sure I have one that will fit though.