Prime Guard RV & Marine Antifreeze 1 gal (Pack of 6) -50°F protection, non-toxic glycerin-free formula

Prime Guard -50 RV & Marine Antifreeze is a non-toxic, glycerin-free winterizing fluid formulated to protect plumbing and engines down to -50°F while remaining safe for copper, brass and most plastics.

Designed for RVs, boats and seasonal systems, this concentrated antifreeze meets industry standards for burst protection in copper tubing and provides broad material compatibility. It’s formulated to avoid glycerin, reducing crystal formation and improving flow through hoses and traps. The product is labeled safe for incidental contact with people, pets and wildlife, and is effective in extreme cold to protect against freeze damage.

How does Prime Guard protect plumbing and prevent burst pipes?

The formula displaces water in lines and depresses the freezing point so liquid remains unfrozen at very low temperatures, reducing pressure build-up that leads to ruptures. It meets established standards for burst protection in copper piping, ensuring consistent performance when used as directed.

• Protects copper tubing to industry burst-protection criteria
• Effective freeze point protection to -50°F when properly flushed and filled
• Low-viscosity formula flows into traps, elbows and small-diameter lines

Is this antifreeze safe for my RV or boat plumbing materials?

Prime Guard is compatible with copper, brass and most plastic plumbing components, except acetate-based plastics. Because it’s glycerin-free and non-corrosive to common materials, it helps avoid damage or softening that some other products can cause.

• Safe on copper and brass fittings and pipes
• Compatible with PVC, CPVC and most common plastics (not acetate)
• Formulated to reduce risk of material degradation over winter storage

Can I use this around people, pets and wildlife?

Prime Guard is labeled for incidental contact and is formulated to be safer than many automotive glycols; however, it is not a food-grade product. Avoid deliberate ingestion and follow standard handling and disposal practices to keep people and animals safe.

• Reduced toxicity for incidental exposure scenarios
• Clear handling and storage instructions on the label
• Dispose according to local regulations after use

How do I apply and measure for effective winterization?

Flush the freshwater system with clean water, then pump or pour antifreeze into the lines until you see it at each fixture. Use the manufacturer’s recommended volume or follow plumbing diagrams to ensure all traps, valves and appliances receive protection.

• Flush lines first to remove water and contaminants
• Introduce antifreeze until it reaches each outlet and trap
• Refer to RV/boat manuals for system-specific capacities and procedures

Who is this for: Prime Guard -50 RV & Marine Antifreeze is intended for RV owners, boaters, marina operators and anyone winterizing seasonal plumbing systems in cold climates. It’s especially useful for those wanting a low-viscosity, glycerin-free product that protects copper and brass components to industry standards while offering safer incidental contact properties. Choose this pack of six one-gallon containers if you winterize multiple vessels, large systems, or if you prefer to keep a supply on hand for repeated seasonal use.