VW Caddy Sirus DFW Van – Fuel tank size?

[stevelawiw]

Does anyone know if the Sirus conversion affects the standard Caddy tank size of 60litres? The reason I ask is the fuel gauge is inaccurate if I have a standard tank because after 200 miles my gauge reads ¼ full, but it will only take 30 litres at the garage, so if I have a 60litre tank and it will only take 30 litres then the gauge should read ½ full! I want to make sure I never run out of Diesel for obvious reasons.

[falco peregrinus]

This doesn't exactly answer your question, but it might throw a little light on the subject.
Firstly, fuel tanks generally do not have vertical sides from top to bottom. Manufacturers tend to make them weird shapes in order to fit them into weird-shaped places beneath the body where they can't fit anything else. As a result, the fuel gauge very rarely descends down the gauge at the same speed as the fuel is consumed. In my van, for example, the gauge moves very slowly till it gets to the half-way mark, then it plummets rapidly, because the bottom of the tank has a small surface area than half way up to the top does.
The other factor that may be relevant is that even in those rare tanks that do have vertical sides all the way from top to bottom, fitting an incorrect fuel tank level sensor will result in incorrect displays at the fuel gauge. I had a custom-made tank in a 4wd once, and the guys that built it fitted the wrong fuel level sensor, with the result that the gauge still read half full when the tank was empty.
Perhaps there is no alternative but to ask the people who did the conversion?
Falco

[stevelawiw]

Thanks Falco, I did what you suggested and phoned Sirus who were very helpful even tho I didn't buy it from them as it was a second hand purchase.
The answer, for anyone interested, is that they have replaced the fuel tank, but it is in fact two litres bigger than the original! The fuel guage is next to useless because of the difference in tank shape so the best way is to use the tripometer to judge when a garage visit is due.

[Burgerman]

Mines about as accurate. Chrysler. But I just fill it up when its empty and any time I get chance.