1. Quick Notice
Confirm your engine code (6HK1) and original part numbers before ordering. This overhaul rebuild kit contains the cylinder head gasket (1-12111-976-0) plus full gasket set (8-94392-721-3). Verify engine variant (6HK1, 6HK1T, 6HK1-TC) and vehicle model (NPR, NQR, FTR, FVR, FXR). Professional installation required.
2. Description
This engine overhaul rebuild kit is a comprehensive gasket set for the Isuzu 6HK1 diesel engine. The 7.8L inline 6-cylinder engine features a 115mm bore and 125mm stroke with a 17.5:1 compression ratio. The kit includes the cylinder head gasket (1-12111-976-0) and the full gasket set (8-94392-721-3). The cylinder head gasket is constructed from Multi-Layer Steel with precision-formed fire rings around each cylinder bore, sealing combustion pressures, coolant, and oil passages. The full gasket set includes valve oil seals, crankshaft oil seal, oil pan gasket, valve cover gasket, and all necessary seals for a complete engine overhaul. Common applications include Isuzu NPR, NQR, FTR, FVR, FXR trucks, as well as Hitachi excavators and various industrial equipment powered by the 6HK1 engine. Common failure symptoms include external coolant seepage, white exhaust smoke, milky oil, and compression loss. Replacement restores factory sealing integrity.
3. Parameters Table
| Parameter | Specification |
|---|---|
| Engine Code | Isuzu 6HK1, 6HK1T, 6HK1-TC |
| Displacement | 7.8L (7,790 cc) |
| Configuration | Inline 6-cylinder, 24-valve |
| Bore × Stroke | 115 mm × 125 mm |
| Compression Ratio | 17.5:1 |
| Cylinder Head Gasket | 1-12111-976-0 (MLS construction) |
| Full Gasket Set | 8-94392-721-3 |
| Material | MLS steel with elastomer coating |
| Vehicle Fitment | Isuzu NPR, NPR-HD, NQR, NRR, FTR, FVR, FXR |
| Industrial Fitment | Hitachi ZX330-3, Sany SY335 |
| Included Components | Cylinder head gasket, valve seals, oil pan gasket, valve cover gasket, full gasket set |
| Installation | Professional engine mechanic required |
4. Custom Content
Surface Preparation: Both the cylinder head and engine block surfaces must be clean and flat before installation. Remove all old gasket material using a plastic scraper. Do not use abrasive discs on sealing surfaces. Maximum allowable surface distortion is specified in the Isuzu service manual.
Gasket Orientation: The 6HK1 engine requires specific gasket orientation. Install with the part number facing upward. Left-side cylinder head uses a different gasket configuration from right-side on certain engine variants. Verify service manual for exact placement.
Torque Specifications: Tighten cylinder head bolts in the specified sequence (center outward) using multiple progressive stages. Replace head bolts with new units as required by Isuzu specifications.
Complete Kit Content: The overhaul gasket set includes all necessary seals: valve stem oil seals, crankshaft front and rear oil seals, camshaft seals, oil pan gasket, valve cover gasket, intake and exhaust manifold gaskets, water outlet gasket, and O-rings for fuel system components.
5. FAQ (One by One Question and Answer)
Q1: What is the difference between 1-12111-976-0 and 8-94392-721-3?
A1: 1-12111-976-0 is the cylinder head gasket component. 8-94392-721-3 is the full engine overhaul gasket set which includes the head gasket plus all other seals required for a complete engine rebuild.Q2: Which vehicles use the Isuzu 6HK1 engine?
A2: The 6HK1 engine is found in Isuzu NPR, NPR-HD, NQR, NRR, FTR, FVR, and FXR medium-duty trucks, as well as Hitachi ZX330-3 excavators and Sany SY335 excavators.Q3: What are typical head gasket failure symptoms on the 6HK1?
A3: External coolant seepage at the head joint, persistent overheating, white exhaust smoke, coolant in engine oil (milky appearance), and bubbles in the radiator overflow tank.Q4: Does this kit include head bolts?
A4: No. Head bolts are not included and must be ordered separately. Reusing old bolts is not recommended as they may have permanent stretch from previous torque cycles.Q5: How many head gaskets are needed for the 6HK1 engine?
A5: A single cylinder head gasket is required for the inline 6-cylinder 6HK1 engine, as it has one cylinder head covering all six cylinders.