Some classic fuel additives for older cars include lead replacement additives, solutions that protect the engine from ethanol, competition valve lubricants and corrosion inhibitors. Older cars often require fuel stabilizers that are compatible with ethanol fuels and dry gas with an isopropyl alcohol base.
Many fuel additives for older cars are designed to protect the engine components from the ethanol that exists in modern gasoline. The additives protect the engine from the effects of erosion, rust and excessive condensation. All fuel additives for older cars must be ethanol compatible.
Some older vehicles were designed to accept leaded fuels. When using unleaded fuels, owners should add lead replacements to the gas to reduce the risk of valve seat recession. Ethanol can also cause valves to harden. Valve lubrication additives help prevent this problem.
Ethanol corrosion is one of the most common problems for older cars. Corrosion-inhibiting additives protect the engine gaskets, tubes and tanks. Isopropyl-alcohol-based dry gas is one of the most common additives.
The specific additives depend on the vehicle's design and age. Older cars with carburetors are particularly susceptible to ethanol problems. Drivers must look for fuel additives with carburetor protectors. These additives prevent the fuel phase separation that damages the carburetor.