[FlatheadTed]

Ok Glen , I get your reasoning on the copper ,If you add more red liquid to get half a tank then at empty you will have 4 Gal reserve ,if you displace the same amount of Red liquid by adding more rod you may end up still with 4 gal at empty ,Not sure what the solution is I will have to think about it , I think my cars are likely fuller than I think, I don't go below 1/4 ,Ted