HEET® is a fuel additive designed to remove water from your gas tank and prevent fuel line freeze-ups, especially in cold weather. Proper usage ensures your engine performs smoothly and avoids issues related to fuel system contamination. Here’s everything you need to know about using HEET® effectively.
Understanding HEET® Products
HEET® comes in two main types, each designed for different fuel systems and climates:
Standard HEET® (Yellow Bottle)

- Treats Up to: 20 gallons of gasoline.
- Suitable For: All 4-cycle gasoline engines.
- Not Recommended For: 2-cycle engines or diesel engines.
ISO-HEET® (Red Bottle)

- Treats Up to: 20 gallons of fuel.
- Suitable For: All gasoline engines, including 2-cycle engines and diesel engines.
- Additional Benefits: Offers superior water removal and can be used in colder or wetter conditions.
Recommended Dosage
- Standard HEET®: Use one 12-ounce bottle per 20 gallons of gasoline.
- ISO-HEET®: Follow the same dosage—one 12-ounce bottle for every 20 gallons of fuel.
For smaller tanks, use a proportionate amount to avoid overuse.
How to Use HEET®
When to Use It
- In cold climates, add HEET® with every fuel fill-up to prevent water buildup and fuel line freezing.
- In warmer climates, using HEET® every 5,000 miles can help maintain a clean and efficient fuel system.
How to Add HEET®
- Before or After Filling the Tank: Both methods work equally well. Simply pour the contents of the HEET® bottle into your gas tank.
Precautions and Best Practices
Avoid Overuse
- While HEET® is safe, avoid exceeding the recommended dosage.
- For a 20-gallon tank, don’t use more than two bottles at once, as excessive HEET® may dilute your fuel, potentially affecting engine performance.
Check Compatibility
- Standard HEET®: Not suitable for 2-cycle or diesel engines.
- ISO-HEET®: Versatile and safe for all gasoline engines, including 2-cycle mixes and diesel.
Follow Manufacturer Instructions
Always consult your vehicle’s owner manual and the instructions on the HEET® packaging to ensure compatibility with your engine.
Benefits of Using HEET® Properly
Prevents Fuel Line Freeze-Ups
HEET® eliminates water from your gas tank, preventing it from freezing in colder temperatures, which could block fuel flow.
Improves Fuel System Efficiency
Regular use of HEET® helps maintain a clean fuel system, ensuring optimal engine performance and longevity.
Adaptable to Various Conditions
ISO-HEET® is especially effective in colder, wetter environments, while standard HEET® provides excellent water removal for most gasoline engines.
Ensuring Optimal Fuel System Performance
Using HEET® as directed helps maintain your vehicle’s fuel system by removing water and preventing freeze-ups. Adhering to the recommended dosage and application guidelines ensures your engine runs smoothly, especially in varying climates. Always consult your vehicle’s owner manual and product instructions to ensure compatibility and optimal results.


