Fuel Gauge Question

[lfoggy]

On my new RX400H the low fuel warning light comes on when the fuel gauge is indicating about 7/8ths empty. If I fill up immediately I can put in 45 litres of fuel but the manual says the capacity of the tank is 65 litres ! Anybody know at what point on the fuel gauge you are actually nearing running out ? I assume I can can let the needle drop below empty towards the 'R' on the gauge if I want to use the residual 20 litres of fuel but the stern warning in the manual about the consequences of running out have deterred me from testing this out. The inexplicable absence of a 'miles left in tank' indicator does not help here....

[TigerFish]

My Mk1 GS is the same, if I fill up when the light stays on solid, in theory I have about 4½ gallons left in. The annoying thing is, even when I know I have that much left, psychologically I'm still thinking I'm gonna run out any second

[JBPRX400h]

On my new RX400H the low fuel warning light comes on when the fuel gauge is indicating about 7/8ths empty. If I fill up immediately I can put in 45 litres of fuel but the manual says the capacity of the tank is 65 litres ! Anybody know at what point on the fuel gauge you are actually nearing running out ? I assume I can can let the needle drop below empty towards the 'R' on the gauge if I want to use the residual 20 litres of fuel but the stern warning in the manual about the consequences of running out have deterred me from testing this out. The inexplicable absence of a 'miles left in tank' indicator does not help here....

Just a thought. On my company diesel Vectra the low fuel light comes on when there is about 1.5 gallons left (about 50miles) but then starts to flash when the tank is very low (10 miles left?) Does the low fuel light flash on an RX400h when the fuel is about to run out? Does anybody know? Do Lexus know? (I haven't asked them yet!)

In the summer we were travelling down through Belgium late at night when the low fuel light came on. Was going to fill up in Luxembourg anyway as petrol is so much cheaper there but thought we had better put a couple of litres in in Belgium just in case. However, sod's law dictated that there was not another service station before we crossed the border! Managed to make it to the first service station in Luxembourg though without running out but don't know how close we were. Wouldn't want to do that again. Doesn't make for stress free driving!!!!

[lfoggy]

What happens when you run of fuel in a Lexus hybrid ? The manual suggest some sort of apocalyptic end of world event......has anyone experienced this ?

And JBPRX400h, what was your fuel gauge reading when you filled up that time in Luxembourg and how much fuel did you manage to put in ?

[JBPRX400h]

What happens when you run of fuel in a Lexus hybrid ? The manual suggest some sort of apocalyptic end of world event......has anyone experienced this ?

And JBPRX400h, what was your fuel gauge reading when you filled up that time in Luxembourg and how much fuel did you manage to put in ?

If I remember rightly we had travelled about 40-50 mles after the low fuel light came on and the needle on the guage was pointing directly at the E (or is it R?). Just checked back in the receipts and found we put in 59.08 litres which would seem to indicate there was another 6 litres left in the tank but that is very hard to judge as it is difficult to brim the tank. It is very slow putting in the last few litres because the petrol pump keeps shutting off.

Lucky old Luxembourg. Petrol about 82p/litre!!

[JBPRX400h]

What happens when you run of fuel in a Lexus hybrid ? The manual suggest some sort of apocalyptic end of world event......has anyone experienced this ?

And JBPRX400h, what was your fuel gauge reading when you filled up that time in Luxembourg and how much fuel did you manage to put in ?

If I remember rightly we had travelled about 40-50 mles after the low fuel light came on and the needle on the guage was pointing directly at the E (or is it R?). Just checked back in the receipts and found we put in 59.08 litres which would seem to indicate there was another 6 litres left in the tank but that is very hard to judge as it is difficult to brim the tank. It is very slow putting in the last few litres because the petrol pump keeps shutting off.

Lucky old Luxembourg. Petrol about 82p/litre!!

A further update to the fuel guage thread.

Last night the needle was pointing to the top of the line next to the R on the fuel guage (not quite as low as it was in Luxembourg) and it took 56 litres to brim the tank which means there was still a theoretical 9 litres or 60 odd miles left.

[lfoggy]

Right, I'm now determined to hold fire until my needle is right down to the R before filling up....that is if I can stand the yellow fuel gauge light staring at me reproachfully for that long !

[Rillo]

Apparently the 350 has 72 litre tank. I ran mine until trip computer said zero miles left and then filled up - could only get 66 litres into the tank.

[James King]

Apparently the 350 has 72 litre tank. I ran mine until trip computer said zero miles left and then filled up - could only get 66 litres into the tank.

Snap, it does seem very conservative. Top Gear did this a while ago, going past the zero mile, IIRC Clarkson made it back from Milton Keynes to London on the Audi I think he was driving once the guage had said zero miles.

[Rillo]

Another mystery - normally if I fill up to the first nozzle cut off and drive from Berkshire to Durham the needle would be just above the empty mark at the end of the journey of approx 290 miles. However this time I filled up and brimmed until I had filled the neck as well. This time the same journey said I had over a quarter of a tank left for the same journey. Just how random are Lexus fuel gauges??!! :D

[JBPRX400h]

What happens when you run of fuel in a Lexus hybrid ? The manual suggest some sort of apocalyptic end of world event......has anyone experienced this ?

And JBPRX400h, what was your fuel gauge reading when you filled up that time in Luxembourg and how much fuel did you manage to put in ?

If I remember rightly we had travelled about 40-50 mles after the low fuel light came on and the needle on the guage was pointing directly at the E (or is it R?). Just checked back in the receipts and found we put in 59.08 litres which would seem to indicate there was another 6 litres left in the tank but that is very hard to judge as it is difficult to brim the tank. It is very slow putting in the last few litres because the petrol pump keeps shutting off.

Lucky old Luxembourg. Petrol about 82p/litre!!

A further update to the fuel guage thread.

Last night the needle was pointing to the top of the line next to the R on the fuel guage (not quite as low as it was in Luxembourg) and it took 56 litres to brim the tank which means there was still a theoretical 9 litres or 60 odd miles left.

[JBPRX400h]

On my new RX400H the low fuel warning light comes on when the fuel gauge is indicating about 7/8ths empty. If I fill up immediately I can put in 45 litres of fuel but the manual says the capacity of the tank is 65 litres ! Anybody know at what point on the fuel gauge you are actually nearing running out ? I assume I can can let the needle drop below empty towards the 'R' on the gauge if I want to use the residual 20 litres of fuel but the stern warning in the manual about the consequences of running out have deterred me from testing this out. The inexplicable absence of a 'miles left in tank' indicator does not help here....

Here are some more recent figures. I think the maths is correct. Make of them what you will but don't blame me if you run out of petrol!!!!

Assume average fuel consumption of 30 Miles per gallon

I travelled 18.10 miles after reserve light came on before filling tank to the brim

This equates to 0.6 gallons used after reserve light came on assuming 30MPG

It took 53.38 litres to fill up tank to brim

Total tank capacity 65 litres

Therefore there must have been 11.62 litres left in tank at time of filling up

This equates to 2.56 gallons left in tank at time of filling up

Therefore there must be 3.16 gallons left when reserve light comes on (Petrol left in tank plus petrol used after reserve light came on)

This would give 94.78 possible miles till empty after reserve light comes on assuming average consumption of 30MPG

[ihpj]

Personally speaking I wouldn't let the needle fall that far below into 'R' region - wont be doing the fuel filter any favours and straining the fuel pump as you dredge up allsorts of nasties from the depths of the tank. yes, OK sometimes its necessarily (cheap fuel across the border) but really, not something I would choose to put my Lexus (or any other car for that matter) through every time or frequently.

Not criticising folk, just contributing my 2p worth.

[JBPRX400h]

Personally speaking I wouldn't let the needle fall that far below into 'R' region - wont be doing the fuel filter any favours and straining the fuel pump as you dredge up allsorts of nasties from the depths of the tank. yes, OK sometimes its necessarily (cheap fuel across the border) but really, not something I would choose to put my Lexus (or any other car for that matter) through every time or frequently.

Not criticising folk, just contributing my 2p worth.

It's a popular myth that you dredge up all sorts of nasties from the bottom of the tank if you run it near to empty.

The fuel pick up pipe must be at or very near the bottom of the tank or how else does the fuel get into it even when the tank is only half full or 3/4s full or 7/8ths full? Even if some sediment was picked up there are fuel filters in the pipeline and anyway a Lexus tank doesn't get dirty, does it?!!!!!