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Stainless steel bolts are one of the best choices for exhaust bolts. They have anti-rust and anti-corrosion properties that give extra protection under high-temperature cycles.
Although the stainless steel bolts are anti-corrosion, in some cases, using SS bolts in iron threads or using SS bolts on complete SS exhaust would lead to corrosion after some time. To prevent this apply a good amount of copper anti-seize, and avoid using anti-seize which contains graphite.
My experience with stainless steel exhaust bolts is excellent because I was using anti-seize on threads. Later I switched to Grade 8 bolts and found that it has higher tensile strength than stainless steel bolts. Both materials are rust-proof and they are excellent choices for exhaust manifold bolts. Shun steel is also one of the best options I have seen so far.
3 Best Material For Exhaust Bolts
Grade 8 steel is the best material that I have found for the exhaust bolts. Not only it provides anti-rust, and anti-corrosion, but also can be used in various material threads, unlike stainless steel which doesn’t go well with iron threads.
| Exhaust Bolt Material | Is It Good | Reason |
| Grade 8 Steel | Yes | Heat treated, high tensile strength, rust, and corrosion free. |
| Stainless steel | Yes, but not recommended for cast iron threads. | Rust and corrosion-free. Wear resistance and good strength. |
| Shun stainless steel | Yes | High carbon Japanese stainless steel, rust, and corrosion resistance, wear resistance, and good strength |
1: Grade 8 Bolts
Grade 8 bolts are made with high-quality steel, heat treated to achieve solid strength and corrosion resistance. These bolts are also good against rust. Widely known for their strength, tensile strength, and wear resistance.
Thermal expansion on grade 8 bolts is very minimal and makes it one of the best choices for the exhaust manifold. Seizing is also less than regular bolts, but I would highly recommend using anti-seize with grade 8 bolts. Anti-seize ensures that the seizing won’t occur for a very long time. The cost of the grade 8 bolts could be anywhere between $25-30.
2: Stainless Steel
Stainless steel bolts are widely known for their corrosion and rust resistance. One of the huge benefits of stainless steel bolts is that they last longer than regular bolts and they are also better in terms of strength and quality. Stainless steel material properties make the bolts maintenance-free and long-lasting.
The cost of stainless steel bolts is around $50-100.
3: Shun stainless steel
Shun steel has high carbon properties which makes it one the top quality stainless steel. Shun stainless steel has the same properties as ordinary stainless steel but the corrosion resistance is slightly improved and they have less thermal expansion. Can be used with or without the anti-seize compound. The cost of the shun stainless steel bolts is somewhere between $50-100.
What Are Stock Exhaust Bolts Made Of?
Stock exhaust bolts are made of low-carbon mild steel. Mild steel has good hardness but as compared to stainless steel or grade 8 material, mild steel has less strength and corrosion resistance.
Mild steel bolts are cheap and they can pretty much do the job. The only difference between regular or mild steel bolts and higher-grade steel bolts is the tensile strength. For higher tensile strength you are most likely to pay more than regular steel bolts.
FAQs
Q: Can I Use Regular Bolts on Exhaust Manifold?
You can use regular bolts on the exhaust manifold – they work pretty well for a certain time and by the time the regular bolts get rusty and they also get corrosion.
Regular bolts do not have good heat resistance and due to heat, they expand and cause trouble. My recommendation is to use good anti-seize and apply a fair amount of anti-seize before installing regular bolts.
Q: Do I Need Special Bolts for the Exhaust?
You do not need special bolts for the exhaust however, using special bolts like stainless steel, grade 8, or shun steel would be a better choice. Regular bolts have less corrosion resistance than special bolts. Special bolts have higher tensile strength and they provide better protection against rust and corrosion.
Q: Can I Use Never Seez on Exhaust Manifold Bolts?
You can use never seez on exhaust manifold bolts. Never seez is an anti-seize compound that is often used as a threat lubricant for exhaust bolts. The exhaust manifold temperature could go up to 1200 degrees under the max load.
Never seez can provide extra protection for exhaust manifold bolts since they are exposed to high heat and temperature. You can use copper-based never seez for better protection of exhaust bolts.
Keep in mind that due to the heat cycles the anti-seize won’t last too long on the exhaust manifold bolts, so while doing the maintenance of your car, reapply the compound from time to time.
Q: Can You Use Loctite on Exhaust Bolts?
If you are using Loctite on a bolt that often goes through a heat cycle then putting Loctite won’t be useful. Rather than using Loctite, you can use copper anti-seize which works very well under high temperatures as well. Loctite under high temps will fail. In this situation, Anti-seize is the best option for you.
Q: What Type Of Anti-Seize Is Recommended For Exhaust Bolts?
Copper-based anti-seize is the widely known and most recommended compound for exhaust bolts. The copper-based anti-seize can stand at 1200 degrees Celsius, keeping the bolt safe from corrosion during the heat cycles.
Although the copper-based anti-seize can stand against high temps, keep in mind that it doesn’t stay forever. You have to maintain the compound from time to time in order to prevent corrosion risk.
Note: Avoid using the anti-seize which contains graphite. Graphite results in the corrosion of bolts during the heat cycles.
