A bar of soap rubbed over small holes in gas tanks and lines will get you to a permanent repair, although it's dicey on lines that aren't gravity fed, which is, more or less, all modern vehicles. As well, if your fan/drive belt is wearing badly and in danger of imminent failure, soap may help get you to a repair, but there is a slipage trade-off with drive belts (of course, not having a spare belt is kinda stunned, especially a drive belt). Needle nose pliars applied gently to radiator fins at small holes can suffice, although a can of the liquid plug is far better. Anyone ever have any success with those pressurized cans of guck for tire puncture repair ? (I carry real plugs and a hand pump.)