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Precision Cylinder Head Bolts 22321-25000 for Hyundai KIA G4KH
Precision Cylinder Head Bolts 22321-25000 for Hyundai KIA G4KH
Aug . 04, 2025
Cylinder head bolts 22321-25000 used for HYUNDAI KIA G4KH Auto Parts play a critical role in ensuring safe, reliable, and durable engine assembly. As the automotive industry pushes towards higher efficiency, emissions standards, and maintenance reduction, the demand for high-performance head bolts with advanced material technology and precision manufacturing is surging. This in-depth article covers: industry trends, technical parameters, application scenarios, manufacturing process, benchmarking against competitive suppliers, custom solutions, user stories, live data tables and charts, professional FAQs, and more— all aimed at building comprehensive confidence in this essential auto component.
1. Industry Trends & Market Insights
The tightening of international emission standards (Euro 6d, US EPA Tier 3), the leap to turbocharged gasoline direct injection (GDI), and high-value hybrid applications make engine sealing integrity critically important. According to IHS Markit, the global automotive cylinder head bolts market is projected to grow at a CAGR of 5.6% (2023-2028), reaching $1.2 billion by 2028, driven by increasing vehicle parc in Asia-Pacific and precision demands from OEMs like HYUNDAI and KIA.
Major trends:
Transition to high-strength alloy steel grades with anti-corrosion coatings (Zn, Geomet).
Complex shapes and multi-stage forging for improved stress handling.
Deployment of ISO 898-1:2013 and ANSI/ASME B18.2.1 compliant testing and certification for every batch.
Lifecycle extension via anti-fatigue and anti-vibration design enhancements.
OEMs increasing usage of custom head bolts for NVH and engine light-weighting strategies.
2. Product Technical Specifications – Core Value of Cylinder head bolts 22321-25000 used for HYUNDAI KIA G4KH Auto Parts
Product Name
Cylinder head bolts 22321-25000 used for HYUNDAI KIA G4KH Auto Parts
OEM Reference
22321-25000
Applicable Models
HYUNDAI G4KH, KIA G4KH (Theta II 2.0L / 2.4L, GDI, Turbo)
Heat Treatment Quenching & Tempering (in HRC 34-39)
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CNC Thread Rolling Pitch/lead ISO Class 6g
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Surface Coating Zinc/Geomet Passivation
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Laboratory Testing Tensile/Yield, Salt Spray, Crack Detection
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Packing & Traceability Batch code, QR, OEM label
All manufacturing steps are ISO/TS 16949 and ISO 898-1 certified, including 100% torque-capacity and hardness tests.
Surface treatment is environmentally-friendly (RoHS), ensuring corrosion resistance >850 hours NSS per ISO 9227.
Final products are laser-etched with batch codes for complete traceability—critical for OEM aftersales support.
4. Application Scenarios & Technical Advantages
Automotive Engines: HYUNDAI i40, Sonata, KIA Optima, Sportage, G4KH Series (mainly 2.0L/2.4L GDI/turbo). Ensures robust cylinder head clamping and consistent torque-to-yield performance.
Aftermarket Replacement: Used by authorized service centers and independent workshops for engine rebuilds.
Industrial Applications: Small marine/industrial engines (G4KH based derivatives); exceptional corrosion resistance fits shipping, chemical, and light power generation.
Harsh Environments: Treated head bolts show salt spray test resistance >850 hours (ISO 9227), suitable for petrochemical, metallurgy, and water treatment plants.
Case Study #1: Hyundai Fleet Service A Hyundai dealership in Vietnam replaced 96 G4KH engines after a widespread TTY bolt recall. After using Cylinder head bolts 22321-25000 used for HYUNDAI KIA G4KH Auto Parts with ISO batch tracking and extended lifecycle, incident recurrences dropped by 97% and warranty claims decreased by $33,000/year.
Case Study #2: Remanufacturing Workshop - Istanbul A KIA specialist applying these head bolts in turbocharged Optima engines reports average reman customer satisfaction rates of 9.6/10, citing improved leak prevention and easier torque calibration.
Produced by Oujia Engine Parts, a 16-year Tier-1 OEM and after-market supplier (ISO/TS 16949 certified).
Supplier of HYUNDAI dealerships, certified OEMs (Chile, Russia, UAE), and partners with Bosch, Federal-Mogul, and local auto associations.
Test reports from SGS and national quality institutes available upon request.
Dedicated R&D for custom base material blends and advanced multi-stage cold forging. Can supply compliance to specific market standards (KSA, EU, North America) and white-label customization.
Packaging: Rust-preventing sealed, export cartons, QR batch tracking.
Rapid Prototyping: Mold/blank delivery within 14 days.
Just-In-Time (JIT) Delivery: To dealerships/workshops globally (≤10 working days ETD, fastest 4 days regional air express).
Customer Feedback
“We’ve sourced Cylinder head bolts 22321-25000 used for HYUNDAI KIA G4KH Auto Parts for our G4KH rebuild kit clients since 2021. Returned failure rates plummeted by 95% due to ISO-compliant documentation, while assembly time per cylinder head dropped by 15 minutes thanks to dimensional consistency.” — Leading Engine Rebuilder, South Korea
7. FAQ – Professional FAQ
Q1: What is the specific material composition of Cylinder head bolts 22321-25000 used for HYUNDAI KIA G4KH Auto Parts?
A: Typically high-grade alloy steel (SCM435/SAE 4135), containing Chrome (~1%), Molybdenum (~0.15%), and certified trace element control per ISO 898-1. This brings high tensile (≥1000 N/mm²) and fatigue strength.
Q2: What are the main dimensions and thread standards applied?
A: These bolts have M11 x 1.5 mm thread pitch, length 125 mm, with ISO metric thread per ISO 261/965, and are CNC-calibrated for lead and pitch diameter tolerances (6g).
Q3: Which quality control and testing protocols are followed?
A: Each batch is checked for tensile, yield, and hardness (HRC 34-39) using destructive and non-destructive testing (NDT crack/magnetic). Corrosion is tested by 850h neutral salt spray (ISO 9227).
Q4: How is the installation torque specified?
A: Official torque: 25 Nm + 90° + 90° (angle method, torque-to-yield). Installers should use a calibrated digital torque wrench and strictly follow the spiral sequence recommended by HYUNDAI/KIA service manuals.
Q5: What is the difference between TTY (Torque-To-Yield) bolts and standard bolts?
A: TTY bolts stretch slightly during installation, creating a more uniform clamping force and improving cylinder head-gasket sealing. They must not be re-used after removal; always use new ones for optimal reliability.
Q6: Are there OEM and third-party certifications provided?
A: Yes, every delivery includes ISO/TS 16949 certification, material mill sheets, and batch tracking. Additional SGS, CE, and local regulatory certificates available on request.
Q7: How long is the warranty and what after-sales support is available?
A: Standard is 24 months or 70,000 km (whichever comes first), covering dimensional, assembly, and materials failure. 7/24 technical support, free replacements for quality defects, and expert installation advice.
8. Delivery, Warranty, and Trustworthiness
Typical Lead Time: 3-5 days ex-stock, 7-14 days for custom runs.
Warranty: 2 years/70,000km (manufacturing and materials defects)
Packaging: Rust-proof, sealed, labeled with QR code, and OEM part cross-ref.
Customer Support: 7x24h pre- and post-sales technical consulting by certified engine specialists.
Certifications On File: ISO/TS 16949, SGS, country-specific (KSA, Mexico, EU TUV per order)
Batch Traceability: Full digital trace for every batch—builds trust and simplifies claims in OEM/aftermarket.
Why Choose Cylinder head bolts 22321-25000 used for HYUNDAI KIA G4KH Auto Parts?
Proven OE-quality for HYUNDAI and KIA G4KH engine platforms worldwide
Superior life cycle and fatigue resistance compared to conventional aftermarket options (see data above)
Global customer base (Asia, EU, LATAM), fleet and remanufacturing references
