Steam cars of the time needed a lot of preparation that required about 30 minutes or more before they could be driven. On condensing models lubricating oil mixed with the water which then had to be changed every other day or so. Water also would get into the crank case of the engine requiring monthly oil changes. Both types of automobiles at the time where obtaining 8 to 13 miles per gallon of fuel. And the steam car used less expensive fuel oil or kerosene.
Steam automobiles can use a variety of fuels.
The combustion chamber in the boiler can be designed to accommodate any combustible substance. The fuel is burned clean producing no more pollution then a household gas heater. In an automobile the fuel would have to be restricted to one that can be transported and fed automatically. Liquid fuels are the best choice as propane or natural gas are stored under pressure and are vented in case of over pressure creating a danger of explosion. A Stanley, whose pilot had been converted to use propane exploded when vented gas from a spare propane tank carried under the passenger seat ignited killing the driver and injuring the passengers.