Low fuel light

[Stef]

I have my C-max for about two weeks and I would like to know after the low fuel light is on for how long you can drive the car to be on the safe side with the gas; by the way I'm in Canada and it's pretty cold now here.

 

Thanks

[plus 3 golfer]

Welcome Stef, I believe the owner's manual may address this. Under the MY KEY section, the following cannot be changed:

 

"Early low fuel. Warnings are displayed in the information display

control followed by an audible tone when the fuel tank is at

one-eighth tank or less."

 

So, the nominal tank capacity is 13.5 gallon (you'll have to convert to liters).  1/8 tank is about 1.7 gallons.  If you look at the Miles To Empty display, it will likely show less MTE than if one multiplies ones recent fuel economy by 1.7 gallons.   There's no question the MTE is a conservative estimate.  I would start to look to refuel within a serveral miles, if the fuel pump symbol turns red.  I believe owners have driven a good distance (maybe 10+ miles once it turns red).  Those that ran out of fuel will likely chime in.

 

People have a difference of opinion on what is being on the "safe side".  I'd watch the MTE when the low fuel warning comes on and fill up before it drops to an uncomfortable level for you.   People have driven many miles after the MTE shows zero.

 

BTW, it's cold these days too in the mornings in AZ at the golf course: many days around 50 F at tee off and a cool 70 F when finished. :)   Just like what's the "safe side", what's cold to some may be warm to others.

[SPL Tech]

For what it is worth, my understanding is that driving with low fuel frequently can lead to premature damage of the fuel pump. I have heard various reasons as to why this is, but most of the mechanics I have talked to state that fuel pump failure is often attributed to frequently running on empty. I believe there is also a consern with the fuel freezing, with some claiming that a small amount of fuel in a tank can freeze easier than a full tanks.

It is not actually any more expensive to drive with a full tank than with an empty. Either way, the vehicle consumes the same amount of fuel so you mind as well keep it full.

Edited November 21, 2014 by SPL Tech

[ScubaDadMiami]

If you want not to worry about it, you can always carry a gas can with you. Since my 800+ tank, I don't wait until the tank is so close to empty before I fill up. I pretty much know what the car can do, and I doubt that I will try to achieve Jus' 900 tank, so I just don't have the need to push it.

[Marc Smith]

SLP makes a good point.  if you have even the slightest bit of moisture in your tank,  I would imagine  in the cold temps  you may encounter the water freezing in the tank...Also with the empty tank,  since you are taking in atmospheric air(and humidty)  the large volume of air in the tank  leads to potentially more moisture(condensation)

 

That being said.  if you watch the gauge when it turns red.  it will actually show red lines under the lowest E line...IE  like dial guages  you can go below the markings...

 

coupled with the  DTE and the gallons used(reset trip meter at fill up).  I have been filling up after DTE goes to zero, but when the gallons used hits around 12.5 and when I see the red show up below the empty line..

[Bill-N]

For what it is worth, my understanding is that driving with low fuel frequently can lead to premature damage of the fuel pump. I have heard various reasons as to why this is, but most of the mechanics I have talked to state that fuel pump failure is often attributed to frequently running on empty. I believe there is also a consern with the fuel freezing, with some claiming that a small amount of fuel in a tank can freeze easier than a full tanks.

 

It is not actually any more expensive to drive with a full tank than with an empty. Either way, the vehicle consumes the same amount of fuel so you mind as well keep it full.

 

In modern cars, the fuel pump is inside the fuel tank so the fuel actually helps cool the pump.  As the fuel level approaches empty, the pump becomes exposed and thus isn't cooled as much.  The result is reduced pump life.

 

My personal rule-of-thumb is to fill-up when the guage turns yellow.

 

Most cold-weather drivers know, an empty tank is an invitation to a frozen fuel line.  Hence the advice to keep the tank half-full in the winter.  While still good practice, evaporative fuel systems and ethanol blend fuels have largely eliminated that concern.