hi, i currently have a 1.5 tsi fabia as a hire car which I've got to return later today with 2 bars of fuel in. the garage have been a pita so I don't want to over fill it.

How much should I put in to get to 2 bars of fuel costing me the bare minimum?

It's currently showing 30 miles left and red

thanks

I would take someone to watch the fuel gauge while you add fuel, pause, add fuel.

I'm not sure of the MkIV tank capacity, but I'd suggest putting in 10 litres, you could try leaving the ignition on so that you are able to read the gauge while filling. Annoying, but it will be much cheaper to err on the slightly generous side (to the rental co) - the penalty 'refuelling' charges will result in probably the most expensive fuel anywhere!

Edited 9 April, 20251 yr by Warrior193
typo

Lets guess how much your fuel is. 132 pence a litre. £6 a gallon.

Stick in a tenners worth.

Normally hire cars are full when you get them. Garage may assume that you didn't fill it up. Did you mention it was half full when you picked up car or is it noted on the hire agreement? Think they hold 45 litres full.

Alasdair

The tank is 45 litres, if you brimmed it from showing 30 miles range only that might be 50 litres to be up the pipe.

Hopefully @SkodaKing will be along saying how much they put in.

I put in £13.22 and it went up to 135 miles and 3 bars up the scale.

A bit of sport mode later and it arrived with 2 bars 😂

Do tell, what did they do to p155 you off so much? Name and shame.

When we last had a hire car it arrived with a diagram on the paperwork showing where the fuel gauge needle was when the car arrived and the car must be returned or collected with at least the same amount of fuel in it, it was one half of a segment below half full and by a bit of planning that's how it went back without the need to top up from a gallon (5l) can which was the contingency plan.

The Owner's Manual for my UK-specification 2024-built Fabia Mk 4 SE L with 1.0litre motor provides the following advice on Page 121

The fuel tank capacity is approximately 40 litres or 50 litres (depending on vehicle equipment), including a 7 litres reserve.

(A 45 litres capacity is widely quoted online, but I believe this relates to Fabia Mk 3 cars.)

If the on reserve came on at 30 miles range then the car was being driven drinking a fair bit of fuel before then for a few miles. drive it like you stole it or a hire / courtesy car!.

Driven efficiently & getting about 45 mpg it comes on showing 60 miles does it not?

Edited 10 April, 20251 yr by Ootohere

Isn't the range left based on historical information that may not reflect the actual range left because the computer is calculating based on how it was last driven, mpg, over what I don't know, with the computer taking the car to be driven in the same manner and mpg which the driver can alter at will (well as much as the car's computers will allow).

And isn't the reserve in reality just kidology, just a marker same as the red sections on the gauge.

Take the gauges as an estimate rather than an accurate.

The 1974 Rover P6 had a "reserve" it was just a second pipe that went lower in the fuel tank than the other supply pipe, both in same tank that held same amount of petrol.

Pretty much the Reserve light comes on in many vehicles when there is 6 litres in the tank or whatever.

So it matters if you were getting 55 mpg indicated or 27 mpg at that point.

1974 is so 51 years ago...

Edited 10 April, 20251 yr by Ootohere

Let's say my Fabia Mk 4's fuel tank capacity is 40 litres and (as it says in the Owner's Manual) this includes a 7 litres reserve. So, if I fill the tank completely, I'd expect a warning of some sort (light and/or message) to appear indicating that 33 litres of fuel had been used and 7 litres remained. Obviously, if the car has a 'range calculation' capability, there might be an indication of the distance the car might travel before the tank becomes empty, but that distance will depend on how it is driven.

In the 1960s I owned a 600cc AJS motorbike that had a 'saddle' fuel tank with a fuel-tap on each side, with the fuel hoses connected to lead on to the carburettor. One day, knowing I was very low on fuel I turned off the main feed tap and turned on the reserve tap and, returning home later, and several miles from a petrol station, the bike ran out of fuel. I pushed the (heavy) bike for over a mile before thinking to turn the main tap back on, when the bike started immediately - another lesson learned!

15 minutes ago, Ootohere said:

1974 is so 51 years ago...

Yes but it's the same kidology - there is no reserve, unless you carry a gallon (5l) can of fuel in the boot and the can actually has some fuel in it, without fuel in it it's the same as the "reserve" on these cars, non-existent.

Whatever consumption mpg figures the dash shows are historical information showing for that point in time, when driving I can get a current mpg (on a different make and model of car) to show as 99.9 mpg and second(s) later unregistered as under 20 mpg.

The figure(s) shown are are great estimate of how much the computers think you can get if driving in the future mpg is the same as for the period calculated - even the mighty VW can't predicted the future with much accuracy - if they could they'd not have been caught with dieselgate and thrown so many eggs into electric vehicles and China market.

(Almost) all the cars I have ever owned from the late 1970s on have had a fuel reserve warning, of the verbal type, particularly needed on those with fuel tanks of less than 6 or 7 gallons but they might still get a greater range than the cars I had with 12 and 14 gallon tanks.

There is an indication when the car believes you are at the last 6 or 7 litres.

& according to the fuel consumption at that time it gives an indicated range.

If only 30 miles range and you get down hills to the filling station or you lift off the accelerator then you might get 50 miles.

As to the fuel gauge / indicator, you might see full and then vent the tank with ones you can vent and get another 7 litres in.

None of it is rocket science or fuelling rocket.

I asked Brenda (my pet AI) what the 'reserve' of a modern car's fuel tank meant and her reply was as follows.

In modern car fuel tanks, "reserve" refers to the amount of fuel remaining in the tank after the low fuel warning light (or a similar indicator) comes on, typically around 10-15% of the tank's capacity, allowing for a short distance of driving before running out of fuel. 

Brenda then added further detail.

• Low Fuel Warning:

  When the fuel gauge indicates that the tank is nearly empty, a low fuel warning light or a similar indicator will usually illuminate, signaling that the fuel level has reached the "reserve" or "empty" point.

   

• Reserve Fuel:

  The "reserve" or "empty" point is not a separate tank, but rather the point at which the fuel pump can still draw fuel from the bottom of the tank, allowing the car to continue running for a short distance. 

• Distance on Reserve:

  The distance you can drive once the fuel light comes on (or the gauge hits the "empty" mark) varies depending on the vehicle, driving conditions, and fuel efficiency, but it's generally a few tens of miles. 

• Importance of refueling:

  It's important to refill the fuel tank as soon as possible after the fuel light comes on to avoid running out of fuel and potentially damaging the fuel pump.

   

• No Separate Reserve Tank:

  Most modern cars do not have a separate reserve tank; the fuel gauge and fuel pump are designed to ensure that there is enough fuel in the main tank to operate the engine even when the gauge shows "empty".