Dealing with a stubborn fuel leak or a fitting that just won’t seal can be frustrating. The wrong thread sealant can degrade, harden, or crack when exposed to gasoline, leading to drips and dangerous fumes.
This guide reviews five proven thread sealants designed to handle gasoline and ethanol blends. You’ll find the right sealant for your specific application, whether you’re working on a fuel line, carburetor, or pressure sensor.
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Permatex 59214 High Temperature Thread Sealant, 6 ml Tube
Best forSmall high-temp repairs
- Resists high temperatures
- Lubricates threads for assembly
ConsiderVery small tube size
LOCTITE 565 Automotive White Thread Sealant - General Purpose, High Viscosi...
Best forBest Premium
- Withstands up to 10,000 PSI
- OEM-approved performance
ConsiderNot for plastic fittings
Gasoila Thread Sealant for Ethanol E10 & E85 Applications, Non-Hardening, N...
Best forEthanol-blended fuel lines
- Formulated for E10 and E85
- Non-hardening and non-toxic
ConsiderNot for plastic threads
Gasoila Soft-Set Pipe Thread Sealant – Non-Hardening Paste for Metal & Plas...
Best forMixed material plumbing
- Works on metal and plastic
- Wide temperature range
ConsiderSmall tube size
Gasoila Soft-Set Pipe Thread Sealant – Non-Hardening Paste for Metal & Plas...
Best forLarge-scale sealing projects
- Large 1/4 pint volume
- Works on metal and plastic
ConsiderNot ethanol-specific
Permatex 59214 High Temperature Thread Sealant – Compact & Reliable
Brand: Permatex
A compact, high-temp sealant ideal for small, critical repairs.
The Permatex 59214 comes in a small 6 ml tube, but it packs a punch for sealing threaded fittings in high-heat areas. It locks and seals threads while resisting leakage, vibration loosening, and moisture. This formula is also compatible with hydraulic fluids and diesel fuels, making it a versatile option for various automotive applications.
You can reposition parts up to four hours after application, which is helpful when aligning fittings. The lubricating properties make assembly and disassembly easier. However, the small tube size means it’s best for a few specific repairs rather than large-scale projects. If you need a compact, high-temperature sealant for occasional use, this is a solid choice.
- Resists high temperatures
- Lubricates threads for assembly
- Allows repositioning up to 4 hours
- Very small tube size
- Not for large projects
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- Locks and seals threaded fittings
- Resists leakage, vibration loosening, moisture, hydraulic fluids and diesel fuels
- Lubricates threads for easy assembly and disassembly
- Parts may be repositioned up to 4 hours after application
- Suggested Applications: head bolts into through holes, oil PSI sending units and sensors, oil and coolant lines, fuel fittings, rear axle fill plug, brake and power steering fittings
LOCTITE 565 Automotive White Thread Sealant – High-Pressure Performance
Brand: Loctite
A high-pressure sealant perfect for demanding automotive applications.
The LOCTITE 565 is a general-purpose, high-viscosity thread sealant that cures rapidly and can withstand pressures up to 10,000 PSI. It is OEM-approved and trusted by professionals for engine builds. This formula replaces traditional tapes and pipe dopes, offering a versatile solution for stainless steel fittings, head bolts, oil pressure sending units, sensors, and coolant lines.
You’ll appreciate the dependable, leak-proof seal it creates even in demanding conditions. The 50 ml tube provides enough sealant for multiple jobs. While it works well on many materials, it may not be the best choice for plastic fittings. If you need a high-pressure sealant for metal automotive threads, this Loctite product delivers professional-grade results.
- Withstands up to 10,000 PSI
- OEM-approved performance
- Replaces tapes and pipe dopes
- Not for plastic fittings
- Rapid cure may limit work time
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- OEM-Approved Performance: LOCTITE automotive products are not only OEM-specified but also designed and tested by leading auto manufacturers. Trusted by professionals in engine building and repair worldwide (PN: 483629)
- Dependable Thread Sealing: Fast-curing formula withstands pressures up to 10,000 PSI, ensuring leak-proof, long-lasting seals in demanding conditions
- Versatile Alternative: Replaces traditional tapes, pipe dopes, and pre-coated parts, offering a superior solution for a variety of sealing needs
- Wide Application Range: Perfect for stainless steel fittings, head bolts in through holes, oil pressure sending units, sensors, oil and coolant lines, and more
- Specialized Formulation: Engineered specifically for metal and tapered pipe thread fittings, providing a reliable and durable solution for automotive professionals
Gasoila Thread Sealant for Ethanol E10 & E85 – Fuel-Specific Formula
Brand: Gasoila
A specialized sealant for ethanol fuels that stays flexible and reliable.
The Gasoila thread sealant is specifically formulated for ethanol-blended gasoline, including E10 and E85. Its non-hardening, non-toxic formula stays pliable even in cold temperatures, providing a flexible seal that won’t crack or dry out. This makes it an excellent choice for fuel lines and motors where ethanol exposure is a concern.
It is compatible with brass, copper, stainless steel, aluminum, black pipe, tin, and galvanized pipe. Made in small batches in the USA, this professional-grade sealant ensures a secure, leak-proof seal. The 1/4 pint size is generous for multiple projects. If you work with ethanol blends regularly, this sealant is tailored to your needs.
- Formulated for E10 and E85
- Non-hardening and non-toxic
- Works on many metals
- Not for plastic threads
- Paste can be messy to apply
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- Formulated for Ethanol Blends: Specifically designed for ethanol-blended gasoline applications, including E10 and E85, this thread sealant offers a secure, leak-proof seal for fuel line threads and fittings.
- Non-Hardening & Non-Toxic: A non-hardening, non-toxic formula that stays pliable, even in cold temperatures, providing a flexible seal that won’t crack or dry out under extreme conditions, ideal for reliable, long-lasting use.
- Superior Compatibility: Engineered for use on various materials, including brass, copper, stainless steel, aluminum, black pipe, tin, and galvanized pipe, making it a versatile solution for multiple applications. – 100 to 600 Degrees.
- Professional-Grade Design: Made in small batches in the USA, this thread sealant features a convenient brush-in-cap design for precise, mess-free application, ideal for professional-grade performance and ease of use.
- Wide Range of Applications: Perfect for pipe threads, joints, fittings, hoses, nozzles, pump assemblies, fuel lines, oil burners, and more. Suitable for compressors, engines, motors, and hydraulic systems, ensuring a reliable seal.
Gasoila Soft-Set Pipe Thread Sealant – Versatile for Metal & Plastic
Brand: Gasoila
A versatile sealant for mixed materials with excellent temperature tolerance.
The Gasoila Soft-Set pipe thread sealant is a non-hardening paste designed for both metal and plastic fittings. It works on brass, copper, stainless steel, aluminum, ABS, CPVC, PVC, nylon, and more. This versatility makes it ideal for a wide range of plumbing and fuel applications where different materials meet.
Its Soft-Set formula prevents leaks caused by vibration, temperature cycling, and joint movement. It performs in extreme temperatures from -100°F to 600°F, remaining pliable in cold and resisting breakdown in heat. The built-in brush in the cap allows for precise, mess-free application. The 2 oz tube is convenient for small to medium jobs. If you need a sealant that works on both metal and plastic, this is a great option.
- Works on metal and plastic
- Wide temperature range
- Built-in brush for application
- Small tube size
- Not specifically for ethanol
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- Versatile Application for Metals & Plastics – Compatible with brass, copper, stainless steel, aluminum, ABS, CPVC, PVC, nylon, polyethylene, polypropylene, and more, making it ideal for multiple plumbing, HVAC, and industrial projects.
- Soft-Set Formula for Leak Prevention – Non-hardening paste ensures tight seals on pipe threads, joints, and fittings, preventing leaks caused by vibration, temperature cycling, or high pressure, with a thick, high-viscosity consistency.
- Wide Temperature Range for Extreme Conditions – Formulated to perform in temperatures from -100°F to 600°F, this sealant remains pliable in cold and resists breakdown in high heat, offering reliable sealing in extreme environments.
- Built-in Brush for Precision Application – Includes a brush in the cap for mess-free, precise application, allowing easy control of paste placement on threads and fittings without drips or excess residue.
- USA-Made in Small Batches for Quality – Proudly manufactured in Ohio, USA, in small batches for optimal quality control and consistency, providing dependable performance for professional or DIY projects.
Gasoila Soft-Set Pipe Thread Sealant 1/4 Pint – Larger Volume for Big Jobs
Brand: Gasoila
A great value for larger jobs needing a versatile, non-hardening sealant.
This Gasoila Soft-Set pipe thread sealant comes in a 1/4 pint container with a brush cap, offering a larger volume for bigger projects. It shares the same non-hardening formula that works on metals like brass, copper, and stainless steel, as well as plastics such as ABS, PVC, and nylon. The temperature range of -100°F to 600°F ensures reliable performance in extreme conditions.
The brush cap makes application easy and clean, even on larger threads. This sealant prevents leaks from vibration and temperature cycling, making it suitable for both plumbing and fuel systems. If you have multiple fittings to seal or prefer a larger quantity, this size is cost-effective. It’s a practical choice for workshops or frequent repairs where you need a dependable, all-purpose thread sealant.
- Large 1/4 pint volume
- Works on metal and plastic
- Brush cap for easy application
- Not ethanol-specific
- Paste may dry if cap not sealed
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- Versatile Application for Metals & Plastics – Compatible with brass, copper, stainless steel, aluminum, ABS, CPVC, PVC, nylon, polyethylene, polypropylene, and more, making it ideal for multiple plumbing, HVAC, and industrial projects.
- Soft-Set Formula for Leak Prevention – Non-hardening paste ensures tight seals on pipe threads, joints, and fittings, preventing leaks caused by vibration, temperature cycling, or high pressure, with a thick, high-viscosity consistency.
- Wide Temperature Range for Extreme Conditions – Formulated to perform in temperatures from -100°F to 600°F, this sealant remains pliable in cold and resists breakdown in high heat, offering reliable sealing in extreme environments.
- Built-in Brush for Precision Application – Includes a brush in the cap for mess-free, precise application, allowing easy control of paste placement on threads and fittings without drips or excess residue.
- USA-Made in Small Batches for Quality – Proudly manufactured in Ohio, USA, in small batches for optimal quality control and consistency, providing dependable performance for professional or DIY projects.
Buyer’s Guide: What to Consider
Choosing the right thread sealant for gasoline involves a few key factors. Here’s what to consider before making your pick.
- Fuel Compatibility: Ensure the sealant is rated for gasoline and ethanol blends. Some formulas are specifically designed for E10 or E85 to prevent degradation.
- Material Compatibility: Check if the sealant works with your fitting materials. Some are for metal only, while others also seal plastic threads like PVC or nylon.
- Temperature Range: Consider the operating temperature of your application. Sealants vary from -100°F to 600°F, so choose one that matches your environment.
- Hardening vs. Non-Hardening: Non-hardening sealants stay pliable and resist vibration, while hardening types may provide a more rigid seal. Choose based on joint movement.
- Application Method: Look for brush caps or tubes for easy application. Some sealants allow repositioning after application, which can help during assembly.
Conclusion
Selecting the best thread sealant for gasoline depends on your specific needs. For high-pressure metal fittings, the LOCTITE 565 is a top performer. If you work with ethanol blends, the Gasoila ethanol-specific formula is your best bet.
For versatility across metal and plastic, the Gasoila Soft-Set in either size offers reliable performance. The Permatex 59214 is ideal for compact, high-temp repairs. Choose the one that fits your project and enjoy leak-free peace of mind.