After researching manufacturer specifications, industry standards, and thousands of owner reviews, we compared the top gasket sealers on the market. Our evaluation focuses on real-world performance, durability, and safety to help you choose the right sealant for your engine repair. Below are our findings, including honest assessments of each product’s strengths and limitations.
| Photo | Product | Score | Buy |
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Permatex Ultra Black Maximum Oil Resistance RTV Silicone Gasket Maker Best Overall RTV silicone, sensor-safe, low odor, 3 oz tube |
9.2 | 🛒 Check Price |
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Fel-Pro Gasket Sealant CS4560 Runner Up Non-hardening, brush-top can, 1.5 oz |
8.9 | 🛒 Check Price |
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Loctite 5920 High Performance PST Pipe Sealant Best for Threaded Fittings PST, low-torque, 50 ml tube |
8.4 | 🛒 Check Price |
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Right Stuff 1 Minute Gasket Grey Fast Cure RTV silicone, sensor-safe, 9 oz tube |
8.1 | 🛒 Check Price |
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Versachem 91004 Gasket Sealant Budget Pick Non-hardening, 4 oz tube |
7.8 | 🛒 Check Price |
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Hylomar PL32 Universal Blue Gasket Sealant High Temp Specialist Non-setting, temperature range -40 to 350 F |
7.6 | 🛒 Check Price |
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Permatex 82180 Ultra Copper Maximum Temperature RTV Silicone For Extreme Heat RTV silicone, high temp, sensor-safe, 3 oz tube |
7.3 | 🛒 Check Price |
1. Permatex Ultra Black Maximum Oil Resistance RTV Silicone Gasket Maker: Best Overall
Permatex Ultra Black is a top-performing RTV silicone gasket maker that excels in oil-rich environments. Based on owner feedback and the spec sheets, it provides a durable, flexible seal that resists cracking and shrinking. It is sensor-safe and low odor, making it suitable for modern engines with oxygen sensors. The 3 oz tube is convenient for most DIY jobs.
However, this product is not designed for head gaskets or applications requiring high compressive strength. Users report that it can weep if surfaces are not perfectly clean and dry. Skip this if you need a high-temperature sealer for exhaust manifolds or a rigid seal for metal-to-metal joints. For oil pans and valve covers, it is an excellent choice.
- High oil resistance; designed for valve covers, oil pans, and timing covers
- Sensor-safe and low odor; complies with OEM specifications
- Flexible bond withstands vibration and thermal cycling
Pros: Excellent oil and coolant resistance; Easy to apply and cures quickly
Cons: Not recommended for head gaskets or high-torque applications
2. Fel-Pro Gasket Sealant CS4560: Runner Up
Fel-Pro CS4560 is a non-hardening gasket sealant that remains pliable over time, making it perfect for applications where future disassembly is likely. In our evaluation of owner reports, it consistently seals oil pans, valve covers, and water pumps without leaks. The brush-top can allows controlled application even in tight spaces.
Its main limitation is temperature and pressure tolerance. It is not suitable for cylinder heads or exhaust manifolds where high heat can cause it to run or degrade. Also, some users note that it can attract dirt if applied too thickly. Skip this if you need a permanent, high-strength bond; choose it for maintenance-friendly sealing.
- Non-hardening formula stays flexible for easy disassembly
- Brush-top applicator for precise application
- Seals against oil, coolant, and fuel
Pros: Ideal for gaskets that need to be removed later; Works well on paper and rubber gaskets
Cons: Not for high-pressure or high-temp applications
3. Loctite 5920 High Performance PST Pipe Sealant: Best for Threaded Fittings
Loctite 5920 is a premium pipe sealant designed for threaded connections in engines, such as oil pan drain plugs and coolant fittings. Based on manufacturer specs, it provides instant sealing and remains adjustable for a short time. It resists common automotive fluids and is easy to apply from the tube.
However, it is not intended for use as a gasket maker on mating surfaces. Attempting to use it on valve covers or oil pans will likely result in leaks. Also, it may not hold up in high-vibration areas if the threads are not clean. Skip this if you need a traditional gasket sealer; it is best for its intended threaded applications.
- Seals threaded fittings instantly
- Low-torque formula prevents overtightening
- Resists oil, fuel, and coolant
Pros: Works well on pipe threads and fittings; Does not harden completely, allowing adjustments
Cons: Not a gasket maker for flat surfaces
4. Right Stuff 1 Minute Gasket Grey: Fast Cure
Right Stuff 1 Minute Gasket Grey lives up to its name, curing rapidly so you can start the engine almost immediately. According to owner feedback, it works well for oil pans and timing covers when you need a quick turnaround. It is sensor-safe and flexible, accommodating engine movement.
The fast cure is also a drawback: you have very little working time, and if you apply too much, it can squeeze out and create a mess. Some users report skin irritation from contact. It is also not recommended for head gaskets or exhaust manifolds. Skip this if you prefer a slower-curing sealant that allows repositioning; it is ideal for quick fixes.
- Cures in 1 minute for immediate use
- High oil resistance; sensor-safe
- Flexible bond for vibration resistance
Pros: Very fast curing time; Good for emergency repairs
Cons: Can be messy to apply; skin irritation possible
5. Versachem 91004 Gasket Sealant: Budget Pick
Versachem 91004 is a budget-friendly option for hobbyists and light-duty repairs. It is a non-hardening sealant that works well on paper and cork gaskets. In our comparison, it provides adequate sealing for oil pans and valve covers at a lower price point than premium brands.
However, its durability is limited. Owners report that it can dry out and crack after a few years, especially in hot climates. It is not recommended for high-temperature or high-pressure applications like intake manifolds. Skip this if you need a long-lasting seal for critical engine components; it is suitable for occasional use.
- Non-hardening formula for easy disassembly
- Seals against oil, coolant, and fuel
- Works on paper, cork, and rubber gaskets
Pros: Low cost per ounce; Effective for basic gasket sealing
Cons: Not for high-temperature applications; Can dry out over time
6. Hylomar PL32 Universal Blue Gasket Sealant: High Temp Specialist
Hylomar PL32 is a classic non-setting sealant that withstands higher temperatures than many RTV silicones. Based on manufacturer data, it remains flexible from -40 to 350 F, making it suitable for exhaust components and intake manifolds. It resists common engine fluids and allows parts to be removed without scraping.
However, it is not as user-friendly as tube silicones. The paste-like consistency can be tricky to apply evenly, and it may not seal as effectively on rough surfaces. Some owners note that it can weep under pressure if applied too thinly. Skip this if you need a quick, easy application; it is best for those experienced with non-setting sealants.
- Non-setting formula remains flexible indefinitely
- High temperature resistance up to 350 F
- Resists oil, fuel, and coolant
Pros: Good for high-temp applications like exhaust manifolds; Does not harden, allowing disassembly
Cons: Difficult to apply evenly; can be messy; Not as strong as RTV silicones
7. Permatex 82180 Ultra Copper Maximum Temperature RTV Silicone: For Extreme Heat
Permatex Ultra Copper is formulated for extreme heat applications like exhaust manifolds and headers. According to the spec sheet, it handles continuous temperatures up to 700 F and intermittent spikes higher. It remains flexible and sensor-safe.
However, its performance on oil-wetted surfaces is inferior to Ultra Black. Owners report that it may not seal as well on oil pans or valve covers. Also, it requires a longer cure time (up to 24 hours) for full strength. Skip this if you need a general-purpose gasket sealer; it is best reserved for high-heat areas where other sealants fail.
- Withstands continuous temperatures up to 700 F
- Sensor-safe and low odor
- Good for exhaust manifolds and headers
Pros: Excellent high-temperature resistance; Flexible bond for thermal expansion
Cons: Cure time is longer than standard RTV; Not as effective on oil-wetted surfaces
Frequently Asked Questions
What is the best gasket sealer for oil pans?
For oil pans, we recommend Permatex Ultra Black due to its high oil resistance and flexible bond. It is specifically designed for oil-rich environments and is sensor-safe. Ensure surfaces are clean and dry before application.
Can I use gasket sealer on head gaskets?
Most gasket sealers are not recommended for head gaskets because they cannot withstand the high compression and temperature. Head gaskets require precision-fit multi-layer steel or composite gaskets. Use sealers only as a secondary aid if specified by the manufacturer.
How long does RTV silicone gasket maker take to cure?
Cure times vary by product. Standard RTV silicones like Permatex Ultra Black cure in about 1 hour for a low-pressure seal, but full cure may take 24 hours. Fast-cure variants like Right Stuff cure in 1 minute. Always check the product label for specific cure times.
Is it necessary to use gasket sealer with a new gasket?
It depends on the application. Many modern gaskets are designed to be installed dry. However, sealers can be used to fill minor imperfections or to ensure a leak-proof seal on older engines. Overusing sealer can cause leaks or make future disassembly difficult.
What is the difference between hardening and non-hardening gasket sealers?
Hardening sealers (like RTV silicones) cure into a solid rubber-like material that provides a strong, permanent bond. Non-hardening sealers (like Fel-Pro CS4560) remain pliable, making them ideal for applications where parts may need to be removed later. Choose based on whether you prioritize strength or ease of disassembly.
Our Verdict
After researching and comparing specifications, industry standards, and owner feedback, our top pick is Permatex Ultra Black Maximum Oil Resistance RTV Silicone Gasket Maker. It offers the best balance of oil resistance, durability, and ease of use for most engine gasket applications. The runner up is Fel-Pro Gasket Sealant CS4560, which is ideal for those who need a non-hardening sealant for easy future disassembly. Both are excellent choices, but your specific needs may lead you to one of the other specialized options.
