Choosing the right sealant for a water pump gasket is critical to prevent coolant leaks and ensure long-term engine reliability. We researched manufacturer specifications, industry standards, and aggregated owner feedback to evaluate the top products on the market. This guide compares seven real sealants, highlighting their strengths and limitations to help you make an informed decision.
| Photo | Product | Score | Buy |
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Permatex 22071 Water Pump and Thermostat RTV Silicone Gasket Maker Best Overall 3 oz tube, RTV silicone, sensor-safe, low odor |
9.2 | 🛒 Check Price |
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Right Stuff 25223 Grey RTV Gasket Maker Fast Cure 5.5 oz aerosol can, RTV grey, cures in 30 minutes |
8.7 | 🛒 Check Price |
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Loctite 5910 Grey RTV Silicone Gasket Maker High Temp 3 oz tube, RTV silicone, temperature range -85 to 500°F |
8.4 | 🛒 Check Price |
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Fel-Pro 95005 Black RTV Gasket Maker Trusted Brand 3 oz tube, RTV silicone, black, OEM-recommended |
8.1 | 🛒 Check Price |
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ThreeBond 1207B Grey Silicone Gasket JDM Spec 3 oz tube, RTV silicone, OEM for Japanese vehicles |
7.8 | 🛒 Check Price |
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DAP 7079800105 Silicone Sealant Budget Pick 2.8 oz tube, silicone, clear |
7.5 | 🛒 Check Price |
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Versachem 68070 Black RTV Silicone Gasket Maker Heavy Duty 3 oz tube, RTV silicone, black, high-viscosity |
7.3 | 🛒 Check Price |
1. Permatex 22071 Water Pump and Thermostat RTV Silicone Gasket Maker: Best Overall
In our evaluation, the Permatex 22071 stands out as a purpose-built sealant for water pump gaskets. Its RTV silicone formula is designed to withstand the constant exposure to coolant and temperature cycles. Owner feedback consistently highlights its reliable sealing performance and ease of application. We compared its specifications against OEM requirements and found it meets or exceeds them for most vehicles.
However, the 24-hour cure time can be inconvenient for those needing a quick fix. If you require a faster curing sealant, consider an alternative like the Right Stuff. But for a long-lasting repair with minimal risk of failure, this is our top pick.
- Formulated specifically for water pump and thermostat applications
- Sensor-safe and low odor, complies with OEM specs
- Resists coolant, oil, and transmission fluid
Pros: Excellent adhesion to aluminum and cast iron; Easy to apply with precise tip
Cons: Requires 24-hour cure time for full strength
2. Right Stuff 25223 Grey RTV Gasket Maker: Fast Cure
Based on owner feedback and the spec sheets, the Right Stuff 25223 is ideal for those who need a quick turnaround. Its 30-minute cure time allows you to refill coolant and test the system sooner than with traditional RTV. We found the spray application convenient for covering large flange areas evenly.
That said, the aerosol format can be messy and may not be cost-effective for small repairs. Additionally, some users report that the sealant can be difficult to remove later. If you prioritize speed over long-term serviceability, this is a strong choice.
- Cures in 30 minutes to a pressure-tight seal
- Can be used on metal, plastic, and rubber flanges
- Resists coolant, oil, and extreme temperatures
Pros: Fast cure time reduces downtime; Easy spray-on application
Cons: Aerosol can may be wasteful for small jobs
3. Loctite 5910 Grey RTV Silicone Gasket Maker: High Temp
In our research, Loctite 5910 is a premium option for high-temperature applications. Its temperature range exceeds most water pump environments, making it suitable for turbocharged or racing engines. We compared its durability specs against others and found it holds up well under thermal cycling.
However, the cost is higher than many alternatives, and the cure time is standard 24 hours. If you are on a budget or need a fast cure, this may not be the best fit. But for extreme conditions, it is a reliable choice.
- High temperature resistance up to 500°F
- Low volatility, safe for oxygen sensors
- Excellent oil and coolant resistance
Pros: Withstands extreme heat; Good for high-performance engines
Cons: Higher cost per tube
4. Fel-Pro 95005 Black RTV Gasket Maker: Trusted Brand
Fel-Pro is a well-known name in gaskets, and the 95005 is a solid all-around RTV sealant. Based on owner feedback, it works well for water pumps on older domestic cars. We found its performance adequate for standard applications, and the price is reasonable.
However, some users report poor adhesion on plastic thermostat housings. If your water pump flange is plastic, you might need a different product. For metal-to-metal joints, this is a dependable option.
- OEM-recommended for many domestic vehicles
- Resists coolant, oil, and transmission fluid
- Non-corrosive and sensor-safe
Pros: Trusted brand with consistent quality; Good value for the price
Cons: May not adhere well to plastic flanges
5. ThreeBond 1207B Grey Silicone Gasket: JDM Spec
ThreeBond 1207B is the go-to for Japanese vehicles, as it is often the factory fill. In our evaluation, its elastic properties help absorb engine vibrations, reducing the chance of leaks. Owner feedback from Honda and Toyota owners is positive.
The main drawback is availability; it may not be stocked at local auto parts stores. Also, it is not necessarily better than universal options for non-Japanese cars. If you own a Japanese car, this is a solid choice.
- OEM specification for many Japanese cars
- High elasticity for vibration resistance
- Resistant to coolant and oil
Pros: Matches factory sealant for Japanese engines; Good flexibility
Cons: Less common, may be hard to find locally
6. DAP 7079800105 Silicone Sealant: Budget Pick
DAP silicone is a budget option that can work in a pinch. We found that it can seal a water pump gasket temporarily, but it is not designed for constant coolant exposure. Owner feedback indicates mixed results, with some experiencing leaks after a few months.
If you need a permanent fix, we recommend spending more on a dedicated product. However, for a temporary repair or low-pressure system, this can save money.
- Low cost, widely available
- Clear finish, blends with surfaces
- General-purpose silicone sealant
Pros: Very affordable; Good for non-critical seals
Cons: Not specifically formulated for coolant resistance; May degrade over time in coolant contact
7. Versachem 68070 Black RTV Silicone Gasket Maker: Heavy Duty
Versachem 68070 is designed for heavy-duty applications where gap filling is needed. In our research, it holds up well on rough surfaces. Owner feedback notes that it works for water pumps but can be messy due to its thickness.
The high viscosity makes it difficult to achieve a thin, even bead, which is ideal for gasket sealing. If you have a smooth flange, a thinner RTV may be easier to use. This is best for older engines with pitted surfaces.
- High-viscosity formula for gap filling
- Resists coolant and oil
- Works on vertical surfaces without sagging
Pros: Stays in place on vertical flanges; Fills gaps well
Cons: Thick consistency can be hard to spread thin
Frequently Asked Questions
Can I use regular silicone caulk for a water pump gasket?
No, regular silicone caulk is not formulated to withstand coolant, pressure, or temperature cycles. It can degrade and cause leaks. Always use a dedicated RTV silicone gasket maker that is coolant-resistant and sensor-safe.
How long should I let the sealant cure before starting the engine?
Most RTV silicones require 24 hours to fully cure for maximum strength. Some fast-cure products like Right Stuff can be ready in 30 minutes, but we recommend following the manufacturer’s instructions. Rushing can lead to leaks.
Do I need to use a gasket with sealant?
Many modern water pumps use a sealant alone (gasket maker) instead of a pre-cut gasket. However, some applications require both a gasket and sealant. Check your vehicle’s service manual. Using sealant alone on a gasketed joint can over-torque and cause leaks.
What is the best sealant for plastic water pump flanges?
For plastic flanges, use a sealant specifically rated for plastics, such as Permatex 22071 or Loctite 5910. Avoid high-viscosity sealants that may not bond well. Ensure the surface is clean and dry before application.
Can I use the same sealant for thermostat housing and water pump?
Yes, many sealants are suitable for both water pump and thermostat housing. However, verify the temperature range and coolant resistance. Products like Permatex 22071 are formulated for both applications.
Our Verdict
After researching and comparing the options, our top pick is the Permatex 22071 Water Pump and Thermostat RTV Silicone Gasket Maker for its reliable performance, sensor-safe formula, and excellent owner feedback. For those needing a faster cure, the Right Stuff 25223 is a strong runner-up. Choose based on your specific needs for cure time, temperature range, and vehicle type.
Last reviewed and spec-checked: March 4, 2026. We re-check our picks and listings periodically.
