Sinclair Gas Station on Massachusetts Avenue in La Mesa's Casa de Oro district carries DINOCARE-branded TOP TIER gasoline, a detergent formulation that exceeds twice the EPA's 1995 minimum deposit-control standard for all three octane grades. The station doubles as an E-85 flex-fuel outlet through the Pearson Fuels distribution network, one of few La Mesa sites dispensing the 85-percent ethanol blend that California STAR-certified testers at Cali v. Smog verify during biennial smog inspections. Sinclair Oil Corporation, founded May 1, 1916, by Harry F. Sinclair from the assets of eleven small petroleum companies, now operates as a subsidiary of HF Sinclair with crude-oil sourcing from domestic Wyoming refineries. Beyond gasoline, this Massachusetts Avenue site dispenses number-two diesel, sells propane by the gallon rather than exchange-only, and handles basic oil changes — a service stack wide enough that roadside breakdowns towed in by Tow For Less can receive immediate fueling and fluid top-offs on arrival. DINOCARE's additive chemistry, introduced in 2014, meets the automaker-consortium TOP TIER standard endorsed by BMW, General Motors, Toyota, Honda, and Mercedes-Benz for optimal intake-valve cleanliness in port-injection and GDI engine architectures.