Nx fuel tank capacity

[Mongo]

Our 2017 GLS Pajero seems to only use 75lt at most, we have run the tank as low as we are comfortable without running out altogether, eg. fuel light on for a fair while and fuel gauge needle below the empty line, the most we have put in after doing this is just short of 75ltrs, the manual indicates an 88 ltr tank so that’s around 13 ltrs not being used wondering why if this is the case?

[talrusan]

Same for me

Sent from my BLA-L29 using Tapatalk

[nj swb]

Probably doesn't help much, but my NT would often squeeze 80 liters into the tank when the light first came on. Lately, the light doesn't seem to come on at all.

[Keithyv]

Not sure about 'not being used', it just means the low fuel light comes on quite early.

Most I've put in is about 81 litres and I thought I was cutting it fine so I can only believe the 88l is an accurate figure but the gauge & light are just being 'extra careful'....

[erad]

The amount of fuel you can pump into the tank depends a lot on how fast you do it. I have had times when the pump nozzle clicked very early, and I managed to get another 15 L into the tank by carefully and slowly topping it up. I have found that the best way to fill my NW is to get the pump going as fast as possible and listen for the gurgling to start. Then I stop and let it settle down a bit. If I "dribble" the fuel in from the start, it doesn't seem to take as much and it takes forever to get to 'full'.

[Mundy55]

As the fuel tank in elongated, the amount you can get in also depends on the slope of the vehicle. If I filled up with the car on a slight downhill slope I could get up to 85L in. However, bear in mind it is intended for there to be an air space in the tank to allow for fuel expansion in hot weather.

[Muzza]

I had a NP and now a NW and both were the same
The low fuel light comes on at 78lt, however this is based on the vehicle pointing down hill to fill, on flat ground take off 3-4lt and point uphill and take off another 3-4lt
So between pointing uphill and down hill the difference is 6-8lt
Cheers

[onair]

I don't think this is isolated to the Pajero - my previous car (unleaded) was supposed to have a 75L tank - when pushed to the point I was concerned about running out of fuel I think I filled it up with 63L.

Either cars are made quite conservative, or the tank capacity and the usable capacity are two different things. (ie, there's some space where fuel can't drain from or similar to catch some water, dirt, etc)... or maybe a combination of the two?

[nj swb]

I don't think this is isolated to the Pajero - my previous car (unleaded) was supposed to have a 75L tank - when pushed to the point I was concerned about running out of fuel I think I filled it up with 63L.

Either cars are made quite conservative, or the tank capacity and the usable capacity are two different things. (ie, there's some space where fuel can't drain from or similar to catch some water, dirt, etc)... or maybe a combination of the two?

There is also a flip side to this experience.

Years ago I lived in Brisbane, working as a field service engineer. In a VT Commodore wagon I filled up on the north side of Brisbane and headed for Rockhampton. The trip computer hit zero km to empty about 30km out of Rockhampton, and when I filled up, the tank took 3 litres more than its nominal capacity - from memory, it was a 72 litre tank, and it took 75 litres.

[RodMac]

Our 2017 GLS Pajero seems to only use 75lt at most, we have run the tank as low as we are comfortable without running out altogether, eg. fuel light on for a fair while and fuel gauge needle below the empty line, the most we have put in after doing this is just short of 75ltrs, the manual indicates an 88 ltr tank so that’s around 13 ltrs not being used wondering why if this is the case?

My experience with an 88ltr Pajero(2010 NT VRX) tank is thus, heading into Quilpie towing a tandem pop top van and the fuel light comes on,.. oops, should have topped up at Windorah !! hmm 75km to go, light throttle flat country, coast into Quilpie and fuel up at the BP outlet.
Tank took 88 litres !! up to the top of the filler tube. N.B. usually average 15lt/100k when towing and if required can get up over 100km after fuel light comes on not towing.

What all this means is you have a fair safety margin in the tank available for normal useage once the fuel light comes on, my current 2016 NX is the same.

Rod Mac
Sunny Coast

[onair]

My experience with an 88ltr Pajero(2010 NT VRX) tank is thus, heading into Quilpie towing a tandem pop top van and the fuel light comes on,.. oops, should have topped up at Windorah !! hmm 75km to go, light throttle flat country, coast into Quilpie and fuel up at the BP outlet.
Tank took 88 litres !! up to the top of the filler tube. N.B. usually average 15lt/100k when towing and if required can get up over 100km after fuel light comes on not towing.

What all this means is you have a fair safety margin in the tank available for normal useage once the fuel light comes on, my current 2016 NX is the same.

Rod Mac
Sunny Coast

Forgive me if I'm wrong, but I'd be careful about that 'safety margin'. I'm sure that there's some, but from what I understand, tank capacity does not include the filler tube.

I suspect in your case - by filling it up to the neck (putting in 88l) means that you were holding more than 88L of fuel in the car in total - and there was still fuel remaining to start with (albeit possibly mostly unusable fuel)

I think what we're dealing with here is a few different variables:

a) The capacity of the tank (the total amount the tank holds)

b) The unusable fuel capacity (this is the amount of fuel that sits at the bottom of the tank that can't be fed into the engine).

(I am unsure to what extent this is done in cars, but it would make sense that there is a sump to catch some sediments and water. I could be well wrong here as I'm coming from an aviation background with no knowledge of diesel engines - but in aviation we have capacity vs usability, and we drain a little fuel before the first flight of each day to check for sediments and water).

c) The extra fuel capacity that is not rated that you can over fill by filling up the neck of the fuel filler.

So while we're focusing on a - the rated tank capacity, I suspect the total usable fuel capacity is really:

a-b+c

This is all conjecture though - the only way to really know is to drive it until it's empty, then pull the tank off and drain and check how much fuel really remains, and then fill up a completely empty car.

Any volunteers? :-)

[Phree_ed]

Unfortunately this is situation (ab)normal. Here's a note I made for my dealer a couple of years ago which led to no action at all

"Although the distance to empty blanked when it fell below 50km as is normal the tank only took 71.12 to fill after driving an additional 11km so there was a little over 16 litres still in the tank when it was filled and at least 17.5lts when the low level light came on. That meant there was still an additional 121km of range left at the then current auto consumption reading (13.2 l/100) when the tank was filled or 132km when the low level light came on. That's 2.64 times more distance to empty than "quoted".
+10% tolerance is bordering on acceptable but a multiple of 2.64 (264%) needs to be fixed.
Imagine a speedo reading 100kph when you're actually doing 264kph or 38kph at a real 100kph.
Or the temp gauge reading centre of the dial (which I'll call 50%) when the real temp is 164% or conversely overheated full scale when it's really not even warmed up yet."

It's a real pain when towing a van and having to fill up well before you need to.

[Phree_ed]

There is also a flip side to this experience.

Years ago I lived in Brisbane, working as a field service engineer. In a VT Commodore wagon I filled up on the north side of Brisbane and headed for Rockhampton. The trip computer hit zero km to empty about 30km out of Rockhampton, and when I filled up, the tank took 3 litres more than its nominal capacity - from memory, it was a 72 litre tank, and it took 75 litres.

You win some you lose some. Obviously their pump was over reading and you or your employer paid for more fuel than you got. I keep regular consumption figures and I've had cases where I've been charged for up to 10% more than I got but I've also had cases where I've paid for way less than I got. In fact out at Yulara the amount of diesel I put in for the distance I travelled gave me a consumption rate of 5.72lt/100 or 49.4mpg for all the old timers out there. Clearly impossible and a big win for me that day.

[nj swb]

You win some you lose some. Obviously their pump was over reading and you or your employer paid for more fuel than you got.

I don't think so. I knew the sort of economy the vehicle would actually get, and how it compared to its "distance to empty" calculations, and how far I could actually drive for the nominal capacity of the tank. I'd filled the tank to the brim in Brisbane, and filled to the brim again in Rocky. It took 75 litres.

[Scooby]

Also the fuel system is now a common rail system and runs hotter and uses the fuel to cool and lubricate the injectors / fuel system.
The fuel tank hasn’t changed with the different models so maybe MM recalibrated the fuel gauge to keep more fuel in the tank for this reason?