Cylinder Head Gasket Replacement 5-87813948-1 NPR 4HF1 Truck Head Gasket

Cylinder Head Gasket 5-87813948-1 For ISUZU NPR 4HF1 TRUCK

1. Quick Notice

Verify the OEM number 5-87813948-1 on your original gasket set before ordering. This is a complete overhaul gasket set for Isuzu 4HF1 engine, not a single head gasket. Contains multiple gaskets and seals for full engine rebuild. Confirm engine model (4HF1) and truck series (NPR66/NKR66). Select correct head gasket thickness by measuring piston protrusion. Professional engine builder required for installation.

2. Description

The 5-87813948-1 is a complete engine overhaul gasket set for Isuzu 4HF1 4.3L diesel engines. The 4HF1 is an inline 4-cylinder, overhead cam, direct injection diesel with 112mm bore, 110mm stroke, 4,334cc displacement, and compression ratio of 18.5:1 to 19.0:1. Power output ranges from 85 kW (114 hp) at 3,200 rpm to 110 kW (148 hp), with torque up to 460 Nm. Applications include Isuzu NPR66, NKR66, and NQR70 trucks. This master set includes the cylinder head gasket, valve cover gasket, intake and exhaust manifold gaskets, oil pan gasket, front and rear crankshaft seals, valve stem seals, thermostat gasket, water pump gasket, and all necessary O-rings for a complete engine overhaul.

3. Parameters Table

4. Custom Content

Complete Set Content: Includes cylinder head gasket, intake manifold gasket, exhaust manifold gasket, rocker cover gasket (valve cover), oil pan gasket, front crankshaft oil seal, rear crankshaft oil seal, valve stem seals (8 pcs), thermostat housing gasket, water pump gasket, turbocharger gaskets (if applicable), and O-rings for fuel system and cooling system.

Cylinder Head Gasket Thickness Selection: Isuzu offers multiple thickness grades determined by measuring piston protrusion above the block deck at Top Dead Center. Select the thinnest gasket that provides adequate clearance. The head gasket appears as a multi-layer steel (MLS) component with multiple stainless steel layers bonded together — this construction provides superior sealing under high cylinder pressures.

Surface Preparation: Both cylinder head and block surfaces must be thoroughly cleaned with a plastic scraper. No abrasive discs or wire brushes. Apply liquid gasket (silicone RTV) at two locations where the timing cover meets the cylinder block — refer to service manual for exact application points.

Cylinder Head Bolt Torque (M14 bolts): First stage: 98 Nm (72 lb-ft). Second stage: 147 Nm (108 lb-ft). Third stage: +30–60 degrees angle torque. Always install new cylinder head bolts — do not reuse old bolts.

Always replace head bolts with new units, not included in this set.

5. FAQ (One by One Question and Answer)

Q1: What is included in the 5-87813948-1 gasket set?
A1: Complete overhaul gasket set includes cylinder head gasket, valve cover gasket, intake/exhaust manifold gaskets, oil pan gasket, front/rear crankshaft seals, valve stem seals, water pump gasket, thermostat gasket, and O-rings.

Q2: Which Isuzu trucks use this gasket set?
A2: Fits Isuzu NPR66, NKR66, NQR70 trucks equipped with 4HF1 4.3L diesel engine.

Q3: Is this a single head gasket or a full set?
A3: Full overhaul set. Contains multiple gaskets and seals for complete engine rebuild.

Q4: How do I select the correct head gasket thickness?
A4: Measure piston protrusion above block deck at TDC. Isuzu offers multiple thickness grades — select by the smallest measurement.

Q5: Does this set include cylinder head bolts?
A5: No. Head bolts must be ordered separately. Always use new head bolts.

Q6: What is the cylinder head bolt torque specification?
A6: M14 bolts — Step 1: 98 Nm (72 lb-ft), Step 2: 147 Nm (108 lb-ft), Step 3: +30–60 degrees angle torque.

Q7: Does the head gasket require sealant during installation?
A7: No. MLS head gaskets seal without additional sealant. Install dry on clean surfaces. However, apply silicone RTV at timing cover joints.

Q8: What is the compression ratio of the 4HF1 engine?
A8: 18.5:1 to 19.0:1 depending on variant.

Q9: Which year models use the 4HF1 engine?
A9: 4HF1 engine found in NPR66/NKR66 trucks produced from approximately 1992 to 2005, with some variants continuing through 2007.

Q10: Is this gasket set suitable for turbocharged 4HF1 engines?
A10: Confirm your specific engine variant. Some 4HF1 naturally aspirated and 4HF1-T turbocharged variants use the same gasket set. Check original gasket for turbo-specific components.