* The Vehicle's Documentation: Look for the original owner's manual or any paperwork that came with the van. This is the most reliable source.
* The Fuel Filler Door: Sometimes the tank capacity is printed on a sticker on the fuel filler door.
* The Vehicle's Build Sheet (if available): This will specify the options included, which may include the fuel tank size. Ford's ordering system may have records if you have the VIN.
* Physical Measurement (less accurate): Carefully measuring the tank's dimensions can give you an approximation, but this isn't precise and needs to be used cautiously to estimate capacity.
Without one of the above sources, there's no way to definitively answer the question. The tank could range from around 25 gallons to potentially larger, depending on the configuration of the van.
