Steve replied:

I run an 80 series and expect 100 k's on either tank after light comes on... your other idea is false...the tanks will run dry and vehicle will slow down..stop if you keep going ,... if you are quick at changing tanks ( push the button) you can keep it going but don't reckon this is a smart move !!
steve

Stan replied:

I also have an 80 series, and have also got around the 100 Klm after the light has come on. Given that the 100 series has the same size tanks, I think it would be safe to assume that your truck would get roughly the same. I thought the same as you regarding the automatic switch over. I was driving late at night just after purchasing my wagon with the sub tank selected, when it started to splutter. Didnt know what to do, but quickly pushed the sub tank button and she eventually picked up. Given that the sub tank on mine (Standard model) doesn't have a fuel low light, I usually run the sub tank down first, then switch to the main. I don't know if there is any right or wrong way of using the tanks.

Kevin Peacock replied:

I have a 1991 80 series and thought that it had a varning light as the 1995 model does(std Wagon) it doesnt. I have run out of fuel in both tanks and had to pump the fuel pump by hand. It works but I dont recomend it. I was guessing fuel to be about 140kms after i hit empty, I only got 100km's as i was doing 100kph, not city driving. Every car even of the same make and year/model will be slightly different so mabe you should try it when you have fuel in your other tank some time you might need to know this info for your self.. Happy cruising Kevin

Fred replied:

Peter, Note the odometer reading when the light comes on. fill up as soon as possible and note the fuel it takes. Subtract this from the tank capacityand add the approximate amount usedbetween the light going on and filling up. In a Prado, the sub tank will empty completely without draining the main. When the main is switched on it will send some to the sub tank whilst supplying the engine .... so if you're silly enough to then run the main dry there is a very small amount again in the sub. I normally run the sub to near empty, switch to the main and refill when it's warning light glows. At that point I usually take about 120l which means I have about 40 litres up my sleeve.

Peter L replied:

Peter, If your 100 is diesel then there is no transfer pump, the engine merely _Affordable_Storage_Drawers.aspx from & recirculates to whichever tank is selected.

If its petrol then I understand that it should transfer fron the sub to the main when the level in the main reaches a given point, but no transfer from main to sub is available.

Best not to run a diesel dry as there is no lubrication of the injector pump afforded by air.

I know my fuel economy (Approx. 7.5K/Litre City - 8.5K/Litre Country) under various circumstances (load/speed) and also that there is 85 litres AVAILABLE from the main & 45 litres from the sub.
Multiply these figures by YOUR economy to determine your range on each tank.

Wayne replied:

Peter

We have a 100 series petrol. When we still had the factory small sub tank, I found that we had only 30 / 40 kms when the light went on.
For the main tank I work on about 60 kms.

This gives me a fairly good safety margin on the main tank.

In terms of drawing betwen the sub and main, when we first had the long range tank fitted to replace the small sub the float or whatever
was not adjusted properly and the low fuel light never went on.
When we did run out of fuel in the sub tank, we would stop unless you hit the switch to send it to the original main tank very quickly.
Therefore as far as i am concerned, each tank is treated separately.

Rgds

Wayne

(PS we have had the float adjusted now so I have some warning when the fuel will run out (although this is still 180kms away)

Peter replied:

Thank you all for your resposes. I'm glad to learn that I have a much better range than I have been used to. Peter.

James replied:

Yes there is plenty of fuel capacity in the Prado and it does go over 1000k on tour. Don't have either of your tanks emty for an extended period as you will burn out the fuel pump. Apparantly they both run all the time and use circulating fuel for cooling. James