12557840 Upgrade 12.9 Grade Balancer Bolt for GM Harmonic Balancer Crank Bolt, for All gen III and gen IV LS engines except for LS7/LS9. 4.8L 5.3L 6.0L 6.2L LS1 LS2 LS3 LS6 L99 LM7 LR4 LMG LQ4 LQ9 L96

★★★★★ 4.2 91 reviews

US$4.00
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Product details

Management number 237514768 Release Date 2026/07/10 List Price US$4.00 Model Number 237514768
Category
  • ✔Compatible with: 12557840 12.9 Grade Balancer Bolt is specifically designed to provide superior strength and durability for your GM Harmonic Balancer Crank Bolt needs. It is engineered for all Gen III and Gen IV LS engines (excluding LS7/LS9), such as 4.8L, 5.3L, 6.0L, 6.2L LS1, LS2, LS3, LS6, L99, LM7, LR4, LMG, LQ4, LQ9, and L96. The upgrade is crucial for ensuring a tight and secure fit, preventing slippage or failure at high RPMs. With this bolt, you can eliminate concerns about harmonic balancer issues commonly faced with standard bolts.
  • ✔Solves Common Balancer Bolt Failure Issues: The main problems LS engine owners face is the failure of factory-installed harmonic balancer bolts, which can lead to catastrophic engine damage. provides a more secure fit for the harmonic balancer, reducing vibrations, ensuring optimal engine timing, and preventing crankshaft damage. With enhanced tensile strength, this balancer bolt is resistant to wear, stretching, or breaking, ensuring long-term reliability, reduces the risk of crankshaft or engine component damage caused by inadequate fastening.
  • ✔Premium Material: Crafted from high-strength steel with a 12.9 grade rating, this GM harmonic balancer bolt is built for toughness. The premium-grade material offers superior corrosion resistance and wear protection, it is designed to endure high levels of heat and stress, making it perfect for high-performance LS engines that demand top-notch durability.
  • ✔Easy to install: It fits seamlessly into all Gen III and Gen IV LS engines, excluding LS7/LS9, ensuring compatibility across a wide range of models. With precision-engineered threads, it guarantees a tight fit, reducing installation time and effort,
  • ✔After-Sales Service: We offer 24 hours customer service and 1 year product service, If you are encounter product installation, product quality and other problems, please feel free to contact us.
ASIN B0DCZ654DM
Brand X4XZ
Color Silver
Model 12557840
Head Type Hex
Size Name 3/8 in
Metal Type Alloy Steel
Unit Count 1.0 Count
Part Number 12557840
Thread Size 3/8 in
Thread Type Unc
Finish Types Glossy
Manufacturer X4XZ
Thread Class 3B
Thread Style Right Hand, Coarse Pitch, UNC
Fastener Size Standard
Fastener Type Hexagon Bolt
Item Hardness Grade 12.9
Material Type 12.9 Steel
Exterior Finish Machined
Number Of Items 1
Thread Coverage Fully Threaded
Screw Head Style Hex
Manufacturer Grade 12.9 grade
Included Components 12557840 Balancer Bolt
Warranty Description 1 YEAR
EU Spare Part Availability Duration 1 Years

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