Cylinder Head Gasket 8-97144985-1 8971449851 For ISUZU NPR/NQR 4HG1 4.6L Diesel

The Cylinder Head Gasket with OEM numbers 8-97144985-1 (also listed as 8971449851) is a verified OEM-grade direct replacement for ISUZU 4HG1 diesel engines, commonly found in NPR and NQR series trucks. Manufactured to ISUZU's stringent OEM specifications, this Multi-Layer Steel (MLS) gasket seals the combustion chamber, coolant passages, and oil channels, withstanding extreme combustion pressure and temperatures to maintain proper compression, prevent fluid leaks, and ensure optimal engine performance.

• OEM Specification — Verified by ISUZU OEM part numbers 8-97144985-1 and 8971449851
• Precision 1.8mm Thickness with 113mm Bore — Delivers correct compression ratio and sealing performance
• Proven Durability — Multi-Layer Steel (MLS) construction designed for minimal fatigue and maximum reliability
• Broad Compatibility — Fits ISUZU NPR and NQR trucks with 4HG1 engines, as well as ELF and Hitachi excavators

If your cylinder head gasket is failing, you may experience one or more of the following symptoms:

• Engine Overheating — Temperature gauge consistently rising above normal
• Coolant Loss — Unexplained drop in coolant level with no visible external leaks
• White Smoke from Exhaust — Steam-like white smoke indicating coolant entering the combustion chamber
• Oil Contamination — Milky or frothy appearance on the oil dipstick or oil filler cap
• Loss of Engine Power — Significant reduction in engine performance due to compression loss
• Bubbling in Radiator — Air bubbles visible in the radiator or coolant reservoir

How to Determine the Correct Gasket:

• Check the part number on your original gasket
• Verify the thickness requirement for your specific engine variant (4HG1, 4HG1-N, or 4HG1-O)
• Always confirm with the engine serial number for precise identification

Primary Applications — Automotive:

Primary Applications — Construction Equipment:

Our manufacturing and inspection processes ensure every cylinder head gasket meets or exceeds ISUZU OEM standards.

Pre-Installation Checklist:

• Verify gasket thickness matches the original — confirm 1.8mm specification
• The correct gasket thickness is determined by the piston projection from the cylinder block upper surface
• Inspect the cylinder head and engine block sealing surfaces for warpage or damage — resurface if necessary
• Clean all sealing surfaces thoroughly — any debris can cause premature gasket failure
• Check cylinder head bolt threads and replace if damaged
• Use new cylinder head bolts if recommended by the workshop manual

Installation Guidelines (Reference ISUZU workshop manual):

• Ensure the engine is completely disassembled with the cylinder head removed
• Clean the cylinder head and engine block sealing surfaces with appropriate solvent
• Check the flatness of both surfaces using a precision straightedge and feeler gauge
• CRITICAL: Position the new gasket correctly — ensure orientation matches OEM specifications
• Install the cylinder head onto the gasket
• CRITICAL: Follow the angular tightening method specified in the ISUZU workshop manual
• Torque cylinder head bolts in the correct sequence and to the specified torque values
• Reassemble remaining engine components
• Refill with fresh coolant and engine oil
• Start the engine and check for leaks
• Perform a cooling system pressure test to verify seal integrity

Maintenance Schedule:

• Inspection: During any cooling system service or if overheating symptoms appear
• Replacement: Immediately if failure symptoms appear. Also recommended during major engine overhauls

• Packaging: Each cylinder head gasket is securely packed in neutral, color, or custom brand packaging
• MOQ: Small quantity accepted; quantity discounts available
• Main Market: Middle East, Asia, South America, Southeast Asia
• Suitable for: Wholesale distributors, engine rebuild shops, truck repair facilities, construction equipment service centers, and fleet owners