Choosing the right sealant for head bolts is critical to prevent coolant or oil leaks and ensure a proper head gasket seal. We researched manufacturer specifications, industry standards, and aggregated owner feedback to evaluate the top options. Our comparison focuses on performance, durability, ease of use, and safety. Below are our findings.
| Photo | Product | Score | Buy |
|---|---|---|---|
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Permatex 22071 High Temperature Thread Sealant Best Overall Temperature range: -65 to 400 degrees Fahrenheit |
9.2 | 🛒 Check Price |
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Loctite 567 Thread Sealant Runner Up Temperature range: -65 to 300 degrees Fahrenheit |
8.9 | 🛒 Check Price |
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ARP 100-9901 Thread Sealant Best for High Performance Temperature range: -65 to 500 degrees Fahrenheit |
8.7 | 🛒 Check Price |
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Permatex 59214 High Performance Thread Sealant Best Value Temperature range: -65 to 350 degrees Fahrenheit |
8.4 | 🛒 Check Price |
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Loctite 565 Thread Sealant Best for Easy Application Temperature range: -65 to 250 degrees Fahrenheit |
8.1 | 🛒 Check Price |
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Hylomar HPF High Performance Sealant Best Non-Hardening Temperature range: -40 to 350 degrees Fahrenheit |
7.8 | 🛒 Check Price |
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Victor Reinz 035 044 001 01 Thread Sealant Best for German Engines Temperature range: -40 to 300 degrees Fahrenheit |
7.3 | 🛒 Check Price |
1. Permatex 22071 High Temperature Thread Sealant: Best Overall
In our evaluation, the Permatex 22071 stands out for its broad temperature tolerance and compatibility with various fluids. It is a PTFE-based thread sealant that cures to a semi-permanent seal, making it ideal for head bolts where a reliable seal is needed. Owner feedback highlights its effectiveness in preventing leaks even under high heat conditions. We compared its spec sheet with others and found its temperature range to be among the widest.
However, this sealant can be messy if not applied carefully, and some users report that it may harden in the bottle over time. If you prefer a non-setting sealant or need one that allows easy disassembly, consider alternatives. For most head bolt applications, this is a solid choice.
- Seals and locks threaded fittings against vibration and leakage
- Resists gasoline, oil, coolant, and other automotive fluids
- Easy to apply with a brush-in-cap applicator
Pros: Excellent high-temperature resistance; Works well on both metal and plastic fittings
Cons: Can be difficult to remove if over-applied
2. Loctite 567 Thread Sealant: Runner Up
Based on owner feedback and the spec sheets, the Loctite 567 is a reliable thread sealant that offers a good balance between sealing and removability. It is a methacrylate-based sealant that cures to a flexible film, which helps absorb vibration. We found it particularly suitable for head bolts in engines that do not reach extremely high temperatures. Its instant sealing capability is a plus for quick assembly.
That said, its upper temperature limit is lower than some competitors, so it may not be ideal for high-performance or turbocharged engines. If your application runs hot, you might want a higher-temperature option. For standard engines, this is a great pick.
- Medium-strength, removable thread sealant
- Seals instantly and cures to a flexible film
- Resists oil, coolant, and hydraulic fluids
Pros: Removable with hand tools; Good for applications where future disassembly is needed
Cons: Not recommended for extreme high-temp applications above 300°F
3. ARP 100-9901 Thread Sealant: Best for High Performance
We compared the ARP 100-9901 against other high-performance options and found its temperature rating of 500 degrees Fahrenheit to be exceptional. It is formulated specifically for head studs and bolts, making it a top choice for racing or modified engines. Owner feedback from performance builders praises its ability to prevent leaks and galling even under extreme conditions. The inclusion of molybdenum disulfide also helps achieve consistent torque readings.
However, its premium price may be overkill for a standard rebuild. If you are working on a daily driver with moderate heat levels, a more affordable sealant may suffice. For high-output engines, this is the best option we found.
- Specifically designed for head studs and bolts
- Contains molybdenum disulfide for anti-seize properties
- Prevents galling and corrosion
Pros: Excellent high-temp performance; Anti-seize properties aid in torque accuracy
Cons: More expensive than general-purpose sealants
4. Permatex 59214 High Performance Thread Sealant: Best Value
In our evaluation, the Permatex 59214 offers a strong balance of performance and affordability. It is a non-hardening sealant that remains pliable, making it ideal for applications where future disassembly is anticipated. Based on owner feedback, it works well on head bolts in most passenger vehicles. We found its temperature range adequate for typical engines, though not for extreme heat.
The main limitation is its temperature ceiling of 350 degrees Fahrenheit. For high-performance or turbocharged engines, a higher-temp sealant is recommended. If your engine runs within normal ranges, this is a cost-effective choice that gets the job done.
- Non-hardening formula allows easy disassembly
- Seals against air, oil, fuel, and coolant
- Works on tapered and straight threads
Pros: Non-hardening, easy to remove; Good value for the price
Cons: Lower temperature limit than some competitors
5. Loctite 565 Thread Sealant: Best for Easy Application
Based on the spec sheets, the Loctite 565 is a low-strength thread sealant that is extremely easy to apply and remove. It is best suited for low-pressure systems, and some owners use it for head bolts in non-critical applications. We compared its temperature rating and found it lower than most, limiting its use to engines that run cool. Its flexibility is a plus for disassembly.
However, for head bolts that are subject to high heat and pressure, this sealant may not hold up. We recommend skipping this pick if you are rebuilding a high-compression or turbocharged engine. For simple repairs on low-stress engines, it is a convenient option.
- Low-pressure sealant for tapered threads
- Instant seal, cures to a flexible film
- Good for hydraulic and pneumatic systems
Pros: Very easy to apply and remove; Works well on plastic fittings
Cons: Not designed for high-temperature or high-pressure applications
6. Hylomar HPF High Performance Sealant: Best Non-Hardening
We evaluated the Hylomar HPF based on owner feedback and its non-hardening formula. It is popular among classic car enthusiasts who prefer a sealant that does not set hard, allowing for easy future removal. Its temperature range is moderate, and it works well on head bolts in vintage engines. However, we found that it may not provide the same level of leak prevention as curing sealants under high pressure.
If you are working on a modern high-performance engine, this may not be the best choice. For a restoration project where preserving original parts is important, this sealant is a good fit. Its non-hardening nature also makes it forgiving during assembly.
- Non-hardening, remains pliable for easy disassembly
- Resists fuel, oil, coolant, and water
- Suitable for head bolts and gaskets
Pros: Stays soft, no curing time; Can be used as a gasket dressing
Cons: May not seal as effectively under high pressure
7. Victor Reinz 035 044 001 01 Thread Sealant: Best for German Engines
Based on manufacturer specifications, the Victor Reinz thread sealant is engineered for use on European vehicles, particularly those with aluminum cylinder heads. We compared its formulation to others and noted its anti-corrosion additives are beneficial for aluminum threads. Owner feedback from European car owners is generally positive, but some report mixed results on other engine types.
Its temperature range is adequate for most stock engines, but not for extreme use. If you are working on a non-European engine, a more universal sealant may be a better fit. For German or other European engines, this is a specialized option worth considering.
- Specifically formulated for European engines
- Prevents corrosion and galling on aluminum threads
- Seals against oil, coolant, and fuel
Pros: Designed for aluminum heads; Good corrosion protection
Cons: Limited availability in some markets
Frequently Asked Questions
Do I need thread sealant on head bolts?
Yes, in many cases thread sealant is recommended to prevent coolant and oil from leaking through the threads into the combustion chamber or outside the engine. Some head bolts are designed with a pre-applied sealant, but aftermarket sealant provides extra protection.
Can I use Teflon tape instead of thread sealant on head bolts?
We do not recommend Teflon tape for head bolts because it can shred and clog passages, and it may not withstand high temperatures. Liquid thread sealants are preferred as they fill gaps more effectively and resist heat.
How do I apply thread sealant to head bolts?
Apply a thin, even layer to the threads of the bolt, avoiding the first few threads to prevent sealant from entering the oil gallery. Follow the manufacturer’s instructions for curing time before torquing.
What temperature range should I look for in a head bolt sealant?
For most engines, a sealant rated to at least 350 degrees Fahrenheit is sufficient. For high-performance or turbocharged engines, look for ratings of 400 degrees or higher to ensure the sealant does not degrade.
Can I reuse head bolts with old sealant?
It is not recommended to reuse head bolts with old sealant. Clean the threads thoroughly and apply fresh sealant before installation to ensure a proper seal and accurate torque readings.
Our Verdict
After researching and comparing the top sealants for head bolts, the Permatex 22071 High Temperature Thread Sealant earns our top pick for its excellent temperature range, broad fluid resistance, and ease of use. For those needing a removable option, the Loctite 567 is a strong runner up, offering reliable sealing with the ability to disassemble later.
