Valvoline Zerex G05 Antifreeze Coolant Concentrate — 1 Gallon, HOAT long-life protection

Valvoline Zerex G05 Antifreeze/Coolant Concentrate (1 gallon) is a long-life, HOAT formula engineered to protect modern gasoline and diesel engines from corrosion, deposits, freezing and boiling when mixed to recommended ratios.

Zerex is the top OEM-approved coolant line from Valvoline, designed to meet the needs of newer Ford, Chrysler and Mercedes-Benz platforms as well as a wide range of other passenger and heavy-duty vehicles. This yellow concentrate uses high-purity ethylene glycol combined with Hybrid Organic Acid Technology (HOAT) and targeted additives to help safeguard cooling system metals, control deposits, and resist cavitation in diesel engines. Use it either to top off a radiator or to refill after a full system service for long-lasting protection.

How does Zerex G05 protect different engine metals?

Zerex G05’s HOAT chemistry provides balanced corrosion inhibitors that work across aluminum, cast iron, copper and soldered joints. The formula is low in silicates and contains phosphate-free, reduced-pH inhibitors that are compatible with modern alloy components.

• Hybrid Organic Acid Technology for broad metal protection
• Low-silicate and phosphate-free to reduce deposit formation
• Formulated to be safe on aluminum radiators and water pumps
• Includes nitrites to help prevent diesel cylinder liner cavitation

What mixing ratios should I use for seasonal temperature ranges?

Zerex G05 is sold as a concentrate and must be diluted with clean tap or demineralized water. Different mix ratios provide different freeze- and boil-over protection, so match the ratio to your climate and engine needs.

• 50/50 mix: protection from approximately -34°F to 265°F — common, all-season choice
• 60/40 mix: extends freeze protection to about -62°F and raises boiling resistance
• 70/30 mix: for extreme cold, offers freeze protection near -84°F
• Always follow vehicle manufacturer recommendations before choosing a ratio

Is Zerex G05 compatible with hoses, gaskets and plastics?

The formulation is engineered to be gentle on non-metal cooling system parts while maintaining seal integrity and flow. It contains additives that minimize swelling, hardening or deterioration of common elastomers and plastics when used as directed.

• Designed to protect gaskets and hose materials
• Won’t attack painted surfaces when handled properly
• Contains deposit-control agents to keep passages clear
• Bittering agent added to discourage accidental ingestion

What performance and longevity can I expect from one gallon?

A single gallon of concentrate mixed to a 50/50 ratio yields roughly two gallons of ready-to-use coolant, enough for many top-offs or partial refills. Zerex G05 is backed by lab and field testing and carries a 5 year/150,000 mile protection promise against failures caused by freeze-ups or boil-overs when used per instructions.

• 50/50 dilution provides two gallons of coolant from one concentrate gallon
• Batch-tested for consistent chemistry and real-world fleet validation
• Helps maintain radiator, pump and heater core flow by controlling scale
• Includes denatonium benzoate (30–50 ppm) as a bittering safety agent

Who is this for? Valvoline Zerex G05 is aimed at owners and technicians working on modern passenger cars, light trucks and some heavy-duty diesel applications that require a HOAT-style, OEM-compatible coolant. If your vehicle manufacturer specifies G05 or an equivalent low-silicate, phosphate-free antifreeze for aluminum-containing cooling systems — or you want a proven long-life concentrate for seasonal dilution and system maintenance — this product is a practical choice. Always consult your owner’s manual and service guidelines before replacing or topping off coolant.