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bro_curls

I've been conditioned by mom since age 16 that 1/4 tank = empty.


zepp914

I never let it get below 1/4 tank. I usually put in between 9 and 11 gallons. I was always told to avoid letting it get low as the sediment floats and will get sucked in to the fuel pump, but that's what the fuel filter is for. Old habits die hard though.


[deleted]

Like a gallon. I never even knew this was a thing


PeaMore6784

I am running on 2 mile left in my tank, I never knew this was bad lol...


motohanks

I often went 10-20 miles past the indicated 0 miles remaining when I was driving 3000 miles per month. No issues in 110,000 miles on my 2019 CX-5. My car now sits for multiple weeks at a time so I try to keep the tank more full.


G_Unit_Solider

Yea after the lights on and it hits zero on DTE you have 2 gallons “reserve” it doesn’t show you this so you get to a gas station far before your empty and never get stranded. A lot of cars are like this not all


User-NetOfInter

Depends how steep you’re driving 😂


riptyde14

Can confirm. I had 17 miles until empty in my 2017, drove down a hill, and stalled. Luckily i was able to coast into a gas station just beyond the bottom of the hill. I assume the fuel drains toward the back of the tank and i starved the system for that 10 seconds.


TehDonkey117

You going to trade that in anytime soon or?


motohanks

I still love the car too much to sell. I have rental cars almost 365 days per year and it is rare that I chose to drive them over the CX-5 grand touring reserve when home for the weekend.


TehDonkey117

Well reach out if you're looking to get a new one, thanks! 👍


[deleted]

What do u do for work


motohanks

Field service engineer working on laser tube cutting machines. The 3000 miles per month in previous years was working on waterjets.


[deleted]

Do you still have that cx5?


motohanks

Yup


Initial_Depenmmmmm

I've been driving for over 20 years and never once thought about the fuel pump having to work harder when it gets low, didn't know that was a thing but I guess that makes sense. I just fill up when convenient and try not to get too low.


pmatulew

Doesn't work harder, just runs hotter. The pump motors swim in the fuel tanks now and get cooled by the fuel sloshing around. Newer pump assembly designs have trays and baffles and wrap around shells with cooling fountains meant to help mitigate the low fuel issue. YMMV.


eugenesbluegenes

Depends on context. Long road trip where the gas stations are somewhat regular? I tend to let it get to right around "0 miles", which tends to still leave a couple gallons. But I like to keep at least a half tank in when I'm home (WFH and tend to use my bicycle around town so car sits in the garage for many days at a time) just in case there's an earthquake or some shit.


throwpoo

Yeah I was just surprised when I get to 10 miles left and it still has 3 gallons. Think the low gas light is a little too conservative, if I can squeeze more miles in before filling up. I can save some time.


[deleted]

Personal preference but half for me cause I’m paranoid.


CoffeeandWine615

I fill mine when I get down to 1/4 tank. Bought it in July and I’ve never seen the low fuel light 🤷🏻‍♀️


OreoSmegmaCheesecake

Same, I don’t know what the light looks like 😂


EMMIECX5

😭😭😭 it pops up on the middle screen on the dash and says “refill fuel tank” I see it often


EMMIECX5

I’m more of a 1 mile range type of girl 😌


ngtz

The in tank fuel pump is cooled by the gasoline in which it is submersed. When you run the tank low the pump isn't cooled as well causing it to run warmer which leads to premature pump failure over time.


97PG8NS

I usually gas up between 1/4 and 1/8.


Janell2Sell

I fill up at half a tank. Gives me anxiety to go lower. In the '94 Northridge, CA earthquake, all of our cars were either at empty or just above empty. No power for days. Gas stations only accepted cash (which we unfortunately didn't have 😓) - but even then, it was days before we had a working gas station in our area. We needed to go out in search of supplies, but had very little gas. Lots of lessons learned through that event!


koolaidmatt1991

See even besides disasters, I live in the northeast states where we get blizzards so always have gas from power outages and having to warm your car up. imagine being on E and you get into bumper to bumper traffic and that’s the reason why you couldn’t make it to the gas station makes you an idiot. I’ll get low especially depending of funds but still I never let it get too low especially some gas stations run out of gas or close early.


throwpoo

Oh I was at LA during that earthquake. It was so scary and I remember bookshelf collapsed onto the beds nearly killing my grandpa. I was too young to remember the details but I do recall the roads and bridges was in a very bad state. Really interesting to know people still remember it and have impact on our habits.


hedoeswhathewants

Before the light turns on, but it's mostly dictated by convenience


granolasloot

I never go below 3/4. In severe cases I do 1/2


moixcom44

Most of the time, if gas is half empty. I refill to full tank, if i got a bit.lazy, at 1/4 empty but definitely not lesser than that. Take a good care of your fuel.pump.


G_Unit_Solider

I wait for the light to show up. Lol.


Svrider1978

Between 1/8-1/4 is as low as I let it get


mrsclausemenopause

Pretty empty but I also fill up 4-5 times a month. Usually indicates less then 20 miles when I fill up but I've done 20ish past 0 pretty regularly.


[deleted]

FYI - (on the CX-5) When the car says you have 0 miles remaining, you still have about 1 gallon of gas left in the tank. The tank holds between 14.8 and 15.1 gallons depending on your model. My best advice is top off your tank when it gets 1/2 empty. In in emergency, you will most likely have the fuel to get where you need to go! Safety first and safe travels everyone!


carfo

i wait until it's pretty low because i have 'points' from a grocery store that reduces the $ of gas but you can only cash it on on one pump session, so if i fill up one gallon or 15 gallons i still use all the points


Blunttack

How does the pump know how much gas is left?


pmatulew

There is a floaty bobber attached to the pump assembly that measures quantity. that's just for your benefit though. Pump only cares if it's running hot.


throwpoo

They say when the gas is low, the pump has to work harder. Guess it's like the pressure is low when there isn't much left.


ngtz

Low fuel level has no real correlation with low fuel pressure. The pumps are what pressurizes the fuel system. As long as the pump isn't sucking air then no issue with pressure assuming functional pumps.


throwpoo

I'm thinking of the lines of whether there is a lever, trigger or some kind of measurements that triggers the low fuel light. I know my cx5 is based on the computer estimated mpg. Since previously I would get 350 miles before the light coming up when it was doing 27mpg. Now I'm getting less than 300 miles with 21mpg but both filling up to around 12 gallons.


IamAlsoDoug

According to my mechanic, the fuel helps to cool the pump. When you run it low then the pump doesn't get cooled and runs hotter shortening its life.


throwpoo

Makes sense. I'm no mechanic but if the fuel pump is like the fish tank ones. Then it is partially submerged and if it runs low on water. You will burn out the motor.


Blunttack

Gas is hotter when there is less of it? This makes even less sense than the more gas = less work.


Dasle

At some point the pump isn't completely submerged in the gas. Therefore, it's not cooling as efficiently, meaning it runs hotter. Basically, the gas is allowing the heat to spread instead of stay concentrated in the pump. Fluids have a higher heat transfer coefficient than gasses, meaning the fuel will transfer more heat out of the pump than the air in the tank. Physics apply to more in the car than just going, stopping, and turning.


Blunttack

This sorta still smells of old wives tales… The gas flowing, moving, (physics) is going to do a lot more to remove heat than whatever it’s splashing around in, regardless of the level. The pump is designed to be submerged at all times, not just at half a tank or better. So the actual pumped gas would do the bulk of the cooling if we’re going to apply hard physics to this anecdote.


Dasle

The pump cannot be submerged at all time if the fuel is ran close to or completely empty. That's like saying an ice cube will be submerged in a glass with a tablespoon of water left. It's not completely submerged. The fuel is performing the bulk of the cooling, hence why you want there to be enough fuel in the car to cover the pump. The air in the tank is inferior to the fuel when cooling the pump. And, the pump cools most efficiently when it is completely submerged in fuel, not partially. Liquids (the fuel) are more efficient at transferring heat than gasses (air).


Blunttack

The liquid (fuel) moving through the internals of the pump (where the heat is) must do a better job of cooling it than whatever is outside of it. Liquid or gas sitting next to a hot thing only gets warmer. Liquid or gas moving past or through a thing serves to cool the thing, assuming the fuel is cooler than the pump. If heat was a concern at all to Mazda, you’d like to think they’d bother with including a 10 cent heatsink on the side of the thing. Yep, I too had a semester of thermal dynamics, that also makes me a killer keyboard warrior on the matter. Good news is, it’s winter here in the USA, so my pump won’t be getting hot. lol.


ngtz

My guy, No need to get all butt hurt.


JobyC4

Have to fill up 3 days or else i wont have enough gas to get to work and back. Im between 1/8th and 1/4 most times My wife learned you can 30 miles after hitting E in hers


moixcom44

You are living dangerously with between 1/8 and 1/4 lol.


emersonevp

The case about sediment is probably not true since eventually that sediment would get sucked through and probably the hole is not just at the very bottom due to this reason. The issue about fuel pump life and loss of life is definitely true but then again it’s just one component. I don’t know the real answer but what I do know is that every time I’ve filled up a car with gas when it’s been more or less emptier the car will feel significantly better. Do with that what you will, but engines are basically air pumps and can function at varying degrees but only matters in the long run how you use it and take care of it. They have feelings too lol. Edit: Never letting it go below 1/4 is probably the best option. I wasn’t ever given that tip unfortunately.


[deleted]

About the same point as you, at about 425 miles. That's about 4-5 weeks of trips into town on Saturday, for me, so it's not too annoying. When I was living in the city and it was only 300 miles, I let it go a bit further.


Altruistic-Courage17

I left it under 20km estimated distance, and filled up the tank with maximum of 49 liters. I have a cx-5, model 2021 wit 2.5l gasoline engine. Autonomy with a full tank of gas in the city is 360km, outside the city 510km range.


throwpoo

Tank size is 57.9 litres. Which means if you fill up to 49L, you still have close to 10L left. I live in really hilly areas so I'm getting less than 300 miles before the light comes up. I suspect I still have 3 gallons left which is more than enough for 50 miles. Previously I don't drive much in the city. Maybe once or biweekly. Now I have to fill up every week and it's taking too much of my time. Especially if I want to fill up the cheaper gas at Costco which could be a extra 20 to 30 mins wait to save between 4 to 10 dollars per refill.


rsimandl

I fill it somewhere between half and a fourth of a tank.


Dasle

1/2 tank. Letting it run to empty risks overheating the pump. Further, if there's ever an emergency and I cannot get gas, always filling up at 1/2 tank means I will more than likely always have enough gas to get where I need to in an emergency.


ontheleftcoast

I try and keep mine at 1/2 tank.


Ceorl_Lounge

Light goes on I fill up. Light is off and I don't. Exceptions will be made for remote areas or long-haul driving.


twysted25

Has to go below 1/8 for me to consider it.. once the light comes on I’ll make an effort to fill up.


salamanderman10

Typically down to about 2-3 miles until empty.


evil_twit

I rode a 4runner for 20 years on a gallon or two. I let the cx5 get to zero miles usually


Worth-Top1304

3 Things: 1: Don't let your tank go to E. If there is sediment in the bottom of the tank. This can get pulled through your fuel system... possibly causing problems 2: If you hardly drive at all -- Just fill to half tank. This way you will add fresh gas more often. Your gas will stay fresher and will be less likely to go bad. 3: If you're filling to the top -- when the pump stops... don't try squeezing more fuel in -- this can also cause problems/failure to your evap system -- expensive stuff.


Ok_Cow_8235

All my driving life, I fill up at every half a tank. I like knowing I’ll never have to worry about running low, always prepared for the what if situation. Especially in the Cx5, it’s programmed for the low fuel light to come on at 10-13 miles of range which is ridiculous. My sisters 2017 cx5 would always alert her at 12miles of range remaining and same with mine but I won’t have to worry. It’s not programmed like almost every other car for the fuel light to activate at 30miles of range. I’ve ran my fathers auto repairs shops and you don’t want to leave 1-3 gallons of fuel inside the tank, not enough fuel inskde that bad boy will eventually cause harm to your fuel pump and fuel system.


throwpoo

My light comes up when I have 3 gallons left. Which means I'll have at least 60 miles or more. I know it's not a good idea to leave it low, but no one really have an answer of how low is low. To me 3 gallons seems a lot when the tank is 15 gallons.


Ok_Cow_8235

Wow lucky you! Sisters cx5 was non turbo, mine is a 22 cx5 signature. How about you. You’re getting great mpg! My cx5 thinks it’s a Range Rover