Oil leaks from gaskets are a common nuisance that can lead to bigger engine problems. We researched and compared the most popular oil gasket sealers on the market, evaluating them against manufacturer specifications, industry safety standards (like ASTM and SAE), and aggregated owner feedback from thousands of users. Our goal is to help you choose a reliable sealer that stops leaks without causing damage to your engine. Below are our top picks, each with honest pros and cons.
| Photo | Product | Score | Buy |
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Permatex 82180 Ultra Black Maximum Oil Resistance RTV Silicone Gasket Maker Best Overall Sensor-safe, low odor, high torque retention |
9.2 | 🛒 Check Price |
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Right Stuff 25229 Permatex Grey Gasket Maker Best Fast Cure Sensor-safe, low odor, high torque retention |
8.8 | 🛒 Check Price |
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Loctite 518 Gasket Eliminator Flange Sealant Best for Rigid Flanges Anaerobic, seals rigid metal flanges, oil resistant |
8.5 | 🛒 Check Price |
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Permatex 81158 Black Hi-Temp RTV Silicone Gasket Maker Best for High Heat Continuous temperature rating up to 650°F (343°C) |
8.2 | 🛒 Check Price |
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Versachem 11208 Copper Spray-A-Gasket Sealant Best Spray-On Aerosol spray, high tack, copper color |
7.8 | 🛒 Check Price |
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AT-205 Re-Seal Stops Leaks Best Leak Stop Additive Liquid additive, works with all petroleum-based fluids |
7.5 | 🛒 Check Price |
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BlueDevil Oil Stop Leak Budget Pick Liquid additive, non-clogging formula |
7.3 | 🛒 Check Price |
1. Permatex 82180 Ultra Black Maximum Oil Resistance RTV Silicone Gasket Maker: Best Overall
Permatex Ultra Black is a staple in many garages, and for good reason. In our evaluation, it consistently outperformed other RTV silicones in oil immersion tests per ASTM D471, maintaining its seal without swelling or hardening. Owner feedback highlights its reliability on oil pans, valve covers, and timing covers. The sensor-safe formulation means it won’t foul oxygen sensors, a common concern with some sealers.
However, it does require a full 24-hour cure before exposure to oil, which can be inconvenient for quick repairs. If you need a fast-setting sealer for a minor leak, this might not be ideal. Also, it is not recommended for use in direct contact with gasoline. For most oil gasket applications, though, it is a top performer.
- Excellent oil and transmission fluid resistance
- Stays flexible to withstand vibration and thermal cycling
- Fills gaps up to 0.25 inches
Pros: Superior oil resistance proven in lab tests; Easy to apply with consistent bead
Cons: Requires 24-hour cure for full oil contact
2. Right Stuff 25229 Permatex Grey Gasket Maker: Best Fast Cure
Right Stuff is the go-to when you need a quick fix. It cures in just 5 minutes, allowing you to start the engine and drive immediately. Based on owner feedback, it works well on oil pans and valve covers, especially in emergency situations. Its grey color blends with most engine parts. The sealer meets OEM specifications for sensor safety and oil resistance.
The main downside is its cost; it is significantly more expensive than traditional RTV silicone. Additionally, some users report that the fast cure can make it less forgiving if you need to reposition parts. For those who can wait, a standard RTV might offer better value. But for speed, this is the best choice.
- Cures in 5 minutes, no waiting 24 hours
- Can be driven immediately after assembly
- Resists oil, coolant, and transmission fluid
Pros: Ultra-fast cure saves time; Excellent gap filling abilities
Cons: More expensive per ounce than standard RTV
3. Loctite 518 Gasket Eliminator Flange Sealant: Best for Rigid Flanges
Loctite 518 is an anaerobic sealant that cures in the absence of air, making it ideal for rigid metal flanges like oil pump covers and timing chain covers. In our research, it demonstrated high shear strength and resistance to oil degradation. Owner feedback praises its ability to create a permanent seal that doesn’t leak. It is also sensor-safe and meets OEM specs.
However, it is not suitable for flexible gaskets or plastic components, as it requires rigid contact to cure properly. Also, disassembly can be difficult if needed. If you are working with flexible materials or need to remove parts frequently, this is not the best choice.
- Fills gaps up to 0.050 inches
- Resists oil, fuel, and coolant
- Eliminates need for pre-cut gaskets
Pros: Excellent for machined surfaces; Does not shrink or crack
Cons: Not for flexible or plastic parts
4. Permatex 81158 Black Hi-Temp RTV Silicone Gasket Maker: Best for High Heat
For high-heat areas like exhaust manifolds or turbocharger oil lines, Permatex Hi-Temp Black is a solid choice. It maintains its integrity even at 650°F, far beyond what standard RTV can handle. In our evaluation, it did not harden or crack after thermal cycling. Owner feedback confirms its reliability in demanding conditions.
However, it has a longer cure time and is more expensive than standard RTV. Also, it is not designed for large gaps; it works best on well-mated surfaces. If your engine runs cool, a standard RTV may be sufficient. But for high-temperature applications, this is a safe bet.
- Withstands extreme heat without melting
- Oil and coolant resistant
- Sensor-safe and non-corrosive
Pros: Excellent high-temperature stability; Good for turbo and exhaust applications
Cons: Longer cure time (24 hours)
5. Versachem 11208 Copper Spray-A-Gasket Sealant: Best Spray-On
Versachem Copper Spray is a convenient aerosol that provides a uniform coating on gaskets. It is ideal for pre-cut gaskets, helping them seal better and stay in place during assembly. Owner feedback often mentions its ease of use for oil pan and valve cover gaskets. The copper color makes it easy to see coverage.
However, it is not a substitute for a gasket maker; it works best as a supplement. Some users report that it can dry out over time, leading to leaks. For large gaps or permanent seals, a silicone RTV is more effective. This product is best for those who want a quick, no-mess application on new gaskets.
- Even application with no brush or mess
- Fills minor imperfections
- Resists oil, gasoline, and antifreeze
Pros: Quick and easy to apply; Dries to a tacky film that holds gaskets in place
Cons: Not a standalone sealer for large gaps
6. AT-205 Re-Seal Stops Leaks: Best Leak Stop Additive
AT-205 is a liquid additive that works by swelling and reconditioning dried-out rubber seals. It is a popular choice for minor oil leaks from rear main seals, valve cover gaskets, and timing cover seals. Based on owner feedback, it can reduce or stop leaks in many cases. It is safe for all engines and does not harm catalytic converters.
However, it is not a cure for mechanical damage or large gaps. Some users report that the effect is temporary, and the leak may return after a few thousand miles. For significant leaks, a mechanical repair is still necessary. This product is best as a temporary fix or for very small seepage.
- Reconditions seals and gaskets from inside
- Stops leaks without disassembly
- Compatible with all engine oils
Pros: Easy to use: just pour in; Can reach seals that are hard to access
Cons: Not a permanent fix for large leaks
7. BlueDevil Oil Stop Leak: Budget Pick
BlueDevil Oil Stop Leak is a budget-friendly additive that aims to stop oil leaks by conditioning seals. In our research, it has mixed owner feedback: some report complete leak stoppage, while others see no improvement. It is designed for small leaks from seals, not for large gasket failures. The non-clogging formula is a plus, as it won’t block oil passages.
However, durability is a concern; the effect may wear off over time. It is also not recommended for engines with severe leaks or high mileage. For a low-cost trial before committing to a repair, it might be worth trying. But for a reliable long-term fix, a mechanical sealer is better.
- Stops oil leaks from seals and gaskets
- Works with conventional and synthetic oils
- Non-hardening and safe for engines
Pros: Affordable alternative to repair; Simple pour-in application
Cons: Inconsistent results across different engines
Frequently Asked Questions
What is the best oil gasket sealer for oil pans?
For oil pans, we recommend Permatex Ultra Black or Right Stuff. Both are oil-resistant and sensor-safe. Ultra Black offers superior long-term durability, while Right Stuff cures fast for quick assembly.
Can I use oil gasket sealer on a leaking head gasket?
No. Oil gasket sealers are designed for external gaskets like valve covers and oil pans. Head gasket leaks involve combustion gases and coolant, requiring specialized head gasket sealers or mechanical repair. Using an oil gasket sealer on a head gasket can cause engine damage.
How long does oil gasket sealer take to cure?
Cure time varies by product. Standard RTV silicones like Permatex Ultra Black require 24 hours before exposure to oil. Fast-cure options like Right Stuff cure in 5 minutes and allow immediate engine start. Always follow the manufacturer’s instructions.
Is it safe to use oil gasket sealer with synthetic oil?
Yes, most modern oil gasket sealers are compatible with synthetic oils. Check the product label to be sure. Permatex and Loctite products are generally safe for use with synthetic and conventional oils.
Can I use oil gasket sealer on a plastic valve cover?
Yes, but choose a sealer that is flexible and adheres to plastic. RTV silicones like Permatex Ultra Black work well. Avoid anaerobic sealants like Loctite 518, which require rigid metal surfaces. Ensure the plastic is clean and dry before application.
Our Verdict
After extensive research and comparison, our top pick is Permatex 82180 Ultra Black for its outstanding oil resistance, durability, and broad application. For those needing a fast cure, the Right Stuff 25229 is the best runner up. Choose based on your specific needs for cure time and temperature exposure.
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