Had the fuel tank assembly replaced in October 2022 with new OEM at dealership. Now it's back in the service shop, because the gauges (on board computer?) do not accurate indicate the amount of fuel left in the tank.
Question: Does anyone know the exact # gallons in an OEM replacement fuel tank for the 2013 JCW (2-dr hatchback, R56)?

Thanks for your input!

COKESTR on the WA Coast

 

A google search has the capacity at 13.2 gallons.

Curious just googled the tank capacity for my 2018 JCW: 11.6 gallons. And this is what a search of tank capacity turns up for my 2023 S, too.

 

And there lies the issue. My owners manual indicates 13.2, yet I'm filling up the tank easily at 14+ without "topping off." It's a bit of mystery - one that I'd like to solve.

 

If you're filling the tank with 14+ gallons, you must be running it pretty low. That like "running on fumes" low!

 

Yep, you are past the reserve or something. Which i would not do as long term it might pick up junk in the gas and get to the fuel filter or HPFP. I am around 13 on fill up.

Stock tank is 50L = 13.2 so you must be getting full all the way up the filler neck?

 

Over the years of filling up and noting how many gallons of fuel is required and the range remaining before I fueled the vehicle I pretty much satisfied myself the stated capacity of the fuel tank was correct. The other day I put 8.3+ gallons of fuel in my 2023. Given the range remaining when I stopped for fuel after I was pretty confident the 11.6 gallons capacity was accurate. As long as I don't encounter a combination of how much fuel the tank takes to reach full and the range remaining that suggests the tank capacity is *less* than the factory claims I'm good.

If the capacity is (in the case of my car) more than 11.6 gallons I would consider that a bonus of sorts. But I would not really rely upon the extra capacity. My SOP is to refuel at between 1/2 and 1/4 full tank. Depends. If I'm in town and with gas stations all over I might take the level down to 1/4 tank. But on the highway to be safe I generally refuel before the level gets to 1/4 full. And more often than not when the level gets to 1/2 I'll fuel up. Just for the extra range having a full tank gives me.

With my style of driving a 1/2 tank of fuel in my S on the highway lets me go an easy 150 miles or more. That's long enough a stop for fuel gives me a bit of a stretch and I can use the bathroom. (Under doctor's orders I am to drink plenty of water.)

Years ago when I had a 2002 VW Golf TDi with a 14,5 gallon fuel tank and that averaged 40mpg I could drive to 400 miles and still have good reserve of fuel. But 400 miles behind the wheel at even 75mph is 5.3 hours and that's a long time behind the wheel with no break.

 

Sorry, but I shake my head any time someone says this. Think about it, if there were sediment in the tank, it would settle to the bottom next to the fuel pickup regardless how much gas was in the tank. Also, that's why the filter is there...

 

Yep, the filter does the job and pick up most of the stuff. I have seen the filter on other cars (not MINI) fail with age and lets junk get through the pleats. Maybe does not do this on the MINI filters (because not everyone one pulls and looks at the filter), but i would not want to risk running the fuel low all the time as the HPFP is lubed by fuel and starving it anyway might hurt it in the long run. Those pumps are delicate.

 

Again, but sorry <shake-my-head> If you're running your tank low enough to interrupt the fuel flow to the HPFP, I hope you're in the gas station parking lot, because your fuel is essentially gone.

Don't get me wrong, I'm not saying everyone should NOT fill up their tank before the light comes on, but you 100% are not going to hurt the car if you wait until the light comes on. I don't even think about heading to the gas station until the light comes on, unless I know I won't have enough range for the current drive.

 

Stuff gets in the fuel tank. But the fuel filter catches the big stuff.

Pic of my Boxster's fuel pump/filter when it needed to be replaced at around 200K miles:



The mesh screen is the fuel filter.

Tech said the amount of sediment trapped by the filter was not bad. And bottom of tank was clean and showed no signs of water.

My concern with running the tank level low is the in tank fuel pump is cooled with fuel. Not visible in the picture but the pump has a small outlet that directs some fuel back into the tank to agitate the fuel and circulate it which helps cool the pump.

If the the fuel tank level is run low -- I consider below 1/4 tank low -- I worry about fuel temperature -- especially on hot days which can have the fuel tank contents 100F or higher as the pump contributes its heat load to the fuel -- and the effect the fuel pump having to operate at a higher temperature over time might have on the low pressure fuel pump in the fuel tank.

 

Is that car also direct injection with a high pressure cam driven pump? I'd be willing to bet that the small outlet from the pump is a bypass or pressure regulator relief.

Here is a cut away for a typical in-tank fuel pump:


As long as there is flow through the pump, the pump is being cooled and lubricated. These things can take much more abuse than you probably think.

But, you can do what you like. I have always run my cars down to the fuel warning light, and I've never changed a fuel pump either.

 

Just feeding fuel to the engine doesn't require much fuel flow. Even with a Hellcat running WOT it takes about 15 minutes to use at least 15 gallons. Tank capacity is just over 18 gallons.

But as I pointed out and while it is not shown in the pic/graphic some fuel is routed back to the tank to agitate the fuel and to ensure circulation of the fuel in the tank to maximize fuel pump cooling. The metal housing of the fuel pump presents considerable surface area to the fuel so this circulation of fuel carries away the heat. But of course their is a finite amount of fuel to absorb this heat.

I'm glad you have had good experiences running the fuel low. But I think there is some luck involved. That's fine. But I don't like to count on having the same good luck you have had so I'll continue to fuel up before the fuel level gets low enough to trigger a low fuel warning.

 

After the shop replaced the entire fuel tank assembly back in October, I actually ran out of gas one night, even though my gauges said otherwise. Until I got it in the shop, I tracked miles/filled tank: ~370 miles/filled tank. And that worked fine. That’s why I asked the question about std # gallons in fuel tank.

Then I got my MINI into the shop last week. Today, the shop sent me this text:

Connected charger and icom. Performed fault survey. No faults stored pertaining to concern. Accessed left and right fuel tank senders as best as possible. Measured readings appear visually to match contents. 0 liters passenger and 2-5 gallons on left side. Accessed senders/floats. Found left side float touching/binding on transfer tubing. Reconfigured transfer lines and checked float swing. Rechecked readings. Now shows slightly over 2 gallons on left side tank. Test drove approximately 12 miles and rechecked readings now 2 gallons. Set for tank fill, qc test drives, and follow up fault/function check. Filled tank and test drove. Performed follow up fault surveys and confirmed repair.

Sharing this with the collective brain trust @ NAM in case someone else has similar problem.

 

Not really related, but this reminds me of the time I put 56L into the tank on my R56 racecar, that only holds 48L !

I had picked up the car from the workshop, on a trailer, and took it to the station on the way home to fill up the tank. Whilst I was filling, someone wandered over and started chatting about the car, asking questions. I got a bit distracted, next thing I saw 56L on the pump. Took a second for my brain to say "does not compute" and stop. Opened up the back of the car and there was 10L of fuel sloshing around where the rear seats used to be

One of things that the car had done while it was in was to check the senders in the tank, as per above post. Turns out they hadn't quite sealed it up properly, and when the tank was full, it just kept overflowing out the top.

BTW you can access the readings from the left and right senders, combined L+R and the buffered fuel level from the secret OBD menu, option 6.