Minimum Safe Fuel Level In Tank

[Hoovie]

I am wondering if there is a recommended minimum amount of fuel that should be left in the tank - or indeed how much fuel is left that the pump cannot get to (assuming that the feed is above the tank bottom to avoid sucking up bits of cr*p that is lying on the bottom?)

The RAV4.2 Petrol Tank is stated in the manual as being 57 Litres.

The Low Fuel light is notoriously unreliable and according to my Scangauge, I have around 80 miles still left to go and about 12 litres left hy the time when that light is constantly on - so I have taken to pretty much ignoring the low fuel light and going by the scanguage data and the trip, BUT how much of that 57 litres is it 'safe' to use before there is a risk of 'nasty' petrol being sucked up?

[Plutus]

Not sure about sucking up the dregs but once got caught out by a computer "miles left" of fuel. Not a Toyota one.

Was showing 12 miles worth left when it ran out quarter of a mile before petrol station on busy dangerous road.

Since then I never trust any gauge. When the gauge goes below a quarter I look to fill up.

[Steve@Aberdeen]

And if anyone saw last Sunday's "Top Gear" they'll know that some gauges go the other way (plenty left once the miles left reaches zero).

Personally, I start looking for a refill once the fuel gauge gets near the red; I've had a low fuel warning light come on once in my Rav4 and a couple times in previous cars - when I get to that it's the next possible pit stop. But then, most of my driving isn't in town with a garage within walking distance

[bothwell_buyer]

please don't go there! I had a ford granada/Scorpio which always ran out 7 miles before getting home from a trip to england. I'm lucky cos I got to know my RAV really well and I feed Shell Vpower into the tank and i know I will get 210 miles unless I am racing. I make sure its never less than 10 litres in the tank. Hopefully if I get to fit a foam filled new tank, I can still remain confident on the fuel left. The gauge is a waste of time.

[Hoovie]

Once calibrated, the Scangauge is very accurate in fact (within 1-2% which equates to 1 litre of fuel) so now I can be slightly more picky about where I fill up - many times on drive home from London in the night time I would be on the low fuel light and looking for an open petrol station, slowing down to 40mph to save fuel and wondering about detours

PS - the range of the RAV4.2 Petrol would seem to be about 375 miles ;)

[anchorman]

The fuel pump is always submerged in a well at the bottom of the tank. This way it will be able to get to the lowest amount possible but it will never normally (unless the car is upside down in a ditch) expose the pump. As long as the pump is submerged it is safe and any arcing at the brushgear is subdued from igniting the tank vapours.

The gauge is notoriously unreliable because it is affected by temperature and Battery voltage. It (and the temperature gauge) actually run at about 9V through a voltage stabiliser so that when you rev the engine the gauges don't respond by moving higher but even so they are not totally reliable. The tank gauge is just a potentiometer and due to the very uneven shape of the tank can vary by large amounts with only very small changes in the inclination of the vehicle. Again the gauge is damped to make it react very slowly to signals from the tank unit otherwise you would have a job to read it as the fuel is surging around inside the tank - it's pretty rough in there!!!

Some lights are operated by a seperate switch and some interpret the gauge readings so they too will be affected. If you note when the light comes on (what milegae) and then fill up at the next opportunity you can work out roughly what is left in the tank. Just use a rule of thumb calc working on the worst case;

eg, 3 gals at 30mpg gives arange of approx 90 miles.

[Parts-King]

Having worked in the motor trade for over 30 years, Salesmen will always run their cars on fumes. The red light will be burning your eyeballs out before it runs out of fuel When the low level warning light comes on the Auris, I am good for at least 35-40 miles. I have never tested it to the running out point but have been close to it when coming back from London and doing a detour off the M6, only to find most fuel stations closed late one night on the A41

Kingo

[Tyler]

I am wondering if there is a recommended minimum amount of fuel that should be left in the tank - or indeed how much fuel is left that the pump cannot get to (assuming that the feed is above the tank bottom to avoid sucking up bits of cr*p that is lying on the bottom?)

The RAV4.2 Petrol Tank is stated in the manual as being 57 Litres.

The Low Fuel light is notoriously unreliable and according to my Scangauge, I have around 80 miles still left to go and about 12 litres left hy the time when that light is constantly on - so I have taken to pretty much ignoring the low fuel light and going by the scanguage data and the trip, BUT how much of that 57 litres is it 'safe' to use before there is a risk of 'nasty' petrol being sucked up?

For what it's worth, according to my handbook it says not to let the fuel go below 1/4 tank.

[Hoovie]

For what it's worth, according to my handbook it says not to let the fuel go below 1/4 tank.

Never noticed that.

[hertsnminds]

For what it's worth, according to my handbook it says not to let the fuel go below 1/4 tank.

Wonder why they don't tell you that in the sales brochure

I sell you a car with a 40 litre tank but you can never let it get below 10 litres, what usable size fuel tank does the car have?

I don't tell you about the 10 litre thing until after you have bought the car (it's in the owners book not the sales book), have I misrepresented the cars features?

If I don't follow the owners guide and do let the tank get below a 1/4 have I invalidated my warranty by not following the manufacturers guideline?

[Bodgit-fixit-run]

So if the gauges are unreliable how accurate is the readout for mpg etc?

[Hoovie]

So if the gauges are unreliable how accurate is the readout for mpg etc?

Perfect!

Mine was never more then 30% out ;)

I used to aim for a OBC readout of 40MPG which woulds tend to give me a real-life 30-32 MPG

PS - I no longer have a Toyota OBC but a Scangauge which, once calibrated, is 1-2% out

[Steve@Aberdeen]

Anyone remember when cars came with a "reserve"? If you ran out of petrol, you turned a tap and got an extra gallon or two.

[chatman]

Anyone remember when cars came with a "reserve"? If you ran out of petrol, you turned a tap and got an extra gallon or two.

Sorry I'm only young and don't remember that.... :rolleyes: I vaguely remember electric windows being common in most cars.... :lol:

Compared to most on here who can probably remember the transition from horse and cart to motor vehicles :yes: :yes:

Now that should start em off...................

[dave.m]

OOOOOooooooooooooo NOOOOOoooooo Chatman you'll get them talking about trains again, probably steam trains

[Hoovie]

I do remember my first car was the DL version of the Vauxhall Viva - DeLuxe, because it had a heater :)

I will also add my first car was 20 years old when I was bequeathed it ;)

[chatman]

I do remember my first car was the DL version of the Vauxhall Viva - DeLuxe, because it had a heater :)

I will also add my first car was 20 years old when I was bequeathed it ;)

Trust Hoovie to lower the tone and mention Vauxhall's..... :!Removed!: :!Removed!: :!Removed!: :!Removed!: :!Removed!: :!Removed!: :!Removed!: :!Removed!:

[bothwell_buyer]

Anyone remember when cars came with a "reserve"? If you ran out of petrol, you turned a tap and got an extra gallon or two.

Can remember that but can't remember which car/s I had wot had that!

[Steve@Aberdeen]

My Dad's MkIII Vanguard had a reserve tap for the fuel tank - a lovely car! 2 litre long stroke petrol engine that could pull anything. I recall us once pulling a caravan up a 1:4 hill (taking a short cut and Dad forgot it was a bit steep)! I learnt to drive in it - a four speed 'box that only really needed 2nd and 4th when solo.

First car I ever drove was a Javelin (I was 12 and it was on a disused airfield) another nice one - four speed 'box with a column change. Can't remember if it had a reserve fuel tap but I do recall it had a second started button under the mat in the passenger floor well.

The first car I owned was an Austin A30 - it was 18 years old when I got it (I was 19), so you beat me there, Hoovie...

[anchorman]

I had a succession of old Mini's - mainly because they were cheap. My mate bought a new Morris 1000 van with two optional extras, a heater and a passenger seat.

I rememer Jowett Javelins though!!!

I use fuel right to the last drop and as long as you use a garage with a reasonable turnover of fuel there is no need to worry about water or other contamination in it.

Don't forget that the fuel pumps are isolated by the airbag/seat pretensioners being activated. If you are unlucky enough to set one off and need to move the car afterwards, you need to turn the ignition off then back on again to override the cut-off. Just make sure fuel isn't pouring out somewhere!!!

[bothwell_buyer]

My Dad's MkIII Vanguard had a reserve tap for the fuel tank - a lovely car! 2 litre long stroke petrol engine that could pull anything. I recall us once pulling a caravan up a 1:4 hill (taking a short cut and Dad forgot it was a bit steep)! I learnt to drive in it - a four speed 'box that only really needed 2nd and 4th when solo.

First car I ever drove was a Javelin (I was 12 and it was on a disused airfield) another nice one - four speed 'box with a column change. Can't remember if it had a reserve fuel tap but I do recall it had a second started button under the mat in the passenger floor well.

The first car I owned was an Austin A30 - it was 18 years old when I got it (I was 19), so you beat me there, Hoovie...

I bought an old A30 and drove it 12 miles to an MOT garage - with only 1 brake working.....but at 25mph along the M8 people liked the novelty of the car!! The car featured in a TV programme, but unfortunately, the bodyshell was too far rusted and it was scrapped.

I remember now that the Triumph Herald had a switchable reserve tank. I had a convertible for some years. And the reserve did come in handy.

The Humber Hawk I have is off the road still awaiting me getting fit enough to crawl around to weld the underneath....1 day???

[Hoovie]

Totally off topic, but as we have now started talking about old cars and what features they had - or didn't have - will give me an excuse to post a pic of the best car I think I have ever had and - until yesterday, when I was emptying loads of drawers and looking at packs of photos- didn't think I had a picture of.

Celica GT-Four ... 4WD Turbo

First car I had that was fitted with ABS Braking; with Aircon; and with Drivers Airbag (I think?).

Oh, and first car I had with 4WD; and a Turbo!

And it was black (I miss that car )