Starting fluid is a volatile, flammable liquid which is used to aid the starting of internal combustion engines, especially during cold weather or in engines that are difficult to start using conventional starting procedures. It is typically available in an aerosol spray can, and may sometimes be used for starting direct injected diesel engines or lean burn spark engines running on alcohol fuel. Some modern starting fluid products contain mostly volatile hydrocarbons such as heptane (the main component of natural gasoline), with a small portion of diethyl ether, and carbon dioxide (as a propellant).[1][2] Some formulations contain butane or propane as both propellant and starting fuel. Historically, diethyl ether, with a small amount of oil, a trace amount of a stabilizer and a hydrocarbon propellant has been used to help start internal combustion engines because of its low 160 °C (320 °F) autoignition temperature.[3]
Diethyl ether is distinct from petroleum ether (a crude oil distillate consisting mostly of pentane and other alkanes) which has also been used for starting engines.[citation needed]