75723. ShellZone Pre-Diluted 50/50 Antifreeze/Coolant, 1 Gal. Shellzone Pre-Diluted 50/50 Antifreeze/Engine Coolant is a high quality, single phase, ethylene glycol based antifreeze. It is a low silicate, all-purpose coolant designed for use in both automotive and heavy duty engines (with the use of SCA's). Price: $6.99 Unit: Each Quantity: