The 4.8L was rated at a peak 175 horsepower in automatic transmission applications and 142 horsepower in applications with a manual transmission. The engine is notable for its low end performance; although the automatic transmission equipped engine produces peak torque at 2,000 RPM, the engine's nearly 5 inch stroke and undersquare bore-to-stroke ratio provide considerable torque at low engine speeds. Transmission options were a Isuzu MXA-5C 5 speed manual, Isuzu MZZ 6 speed manual, or an Aisin-Warner 450-43LE 4 speed automatic. While both the 6 speed manual and 4 speed automatic transmissions feature overdrive, the 5 speed manual transmission's final gear was direct drive (1:1).
4.8L Isuzu 4HE1 Specs
Engine: |
Isuzu 4.8L 4HE1-TC |
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Manufacturer: |
Isuzu Motors Ltd. |
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Applications: |
1999 - 2004 Isuzu NPR |
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Type: |
4 Stroke diesel |
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Configuration: |
Inline 4 cylinder (I-4/L-4) |
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Displacement: |
4.75 liters, 289.96 CID (nominal 4.8 liter/290 CID displacement) |
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Firing Order: |
1 - 3 - 4 - 2 |
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Engine Block: |
Cast iron |
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Cylinder Head: |
Cast iron |
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Cylinder Liner Type: |
Dry |
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Compression Ratio: |
17.3 : 1 |
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Cylinder Bore: |
4.330 inches (110 mm) |
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Cylinder Stroke: |
4.921 inches (125 mm) |
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Valvetrain: |
Single gear driven overhead camshaft (OHC), 2 valves per cylinder |
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Valve Clearance: |
Intake |
0.4 mm |
Exhaust |
0.4 mm |
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Injection: |
Direct injection |
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Aspiration: |
Turbocharged & intercooled |
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Engine Oil Capacity: |
14.5 U.S. quarts (13 liters) |
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Engine Oil Viscosity: |
Varies by ambient operating temperature; see chart below |
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Rated Horsepower*: |
Manual transmission |
142 HP @ 2,800 RPM |
Automatic transmission |
175 HP @ 2,700 RPM |
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Rated Torque*: |
Manual transmission |
275 lb-ft @ 1,300 RPM |
Automatic transmission |
347 lb-ft @ 2,000 RPM |
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Max Engine Speed: |
2800 - 2900 RPM (max RPM @ full load) |
*NPR, NPQ, and GM W4500/W5500 gross horsepower ratings
Transmission Options & Ratios (NPQ/NPR Models)
|
1st |
2nd |
3rd |
4th |
5th |
6th |
R |
Remarks |
Isuzu MXA-5C |
6.020 |
3.626 |
2.017 |
1.367 |
1.00 |
--- |
6.030 |
5 speed manual, synchronized, direct drive |
Isuzu MZZ-6F |
6.369 |
3.767 |
1.966 |
1.355 |
1.00 |
0.782 |
6.369 |
6 speed manual, synchronized, overdrive |
Aisin Warner 450-43LE |
3.018 |
1.548 |
1.000 |
0.703 |
--- |
--- |
2.678 |
4 speed automatic, overdrive |
Isuzu 4.8L 4HE1 Maintenance Schedule
Service Procedure |
Service Interval |
Notes |
Replace engine air filter |
Every 26,000 miles/12 months |
Check condition of air filter at oil change intervals & replace as necessary, or every 26,000 mi/12 mo |
Replace engine oil & oil filter |
Every 6,500 miles/12 months |
Engine oil level should be checked between oil change intervals |
Replace fuel filter |
Every 13,000 miles/12 months |
Replace fuel filter & drain fuel water separator |
Replace engine drive belt |
104,000 miles |
Check condition of drive belt at oil change intervals & replace as necessary; replace regardless at ~100,000 miles |
Drain/replace engine coolant |
Every 26,000 miles/24 months |
Drain/refill cooling system and inspect condition of coolant hoses; replace as necessary |
Adjust valve lash |
Every 52,000 miles |
Set intake & exhaust valve lash to 0.016 in (0.4 mm) |
Replace automatic transmission filter & fluid |
Every 26,000 miles/12 months |
Replace internal and auxiliary transmission filters as applicable |
Replace manual transmission oil |
Every 19,500 miles/12 months |
Drain/refill transmission |
Replace rear differential oil |
Every 26,000 miles/24 months |
Drain/refill differential |
Isuzu 4.8L 4HE1 Oil Viscosity Chart
Oil Viscosity |
Ambient Temperature Range |
SAE 10W-30 |
-20° F to 90° F |
SAE 10W-40 |
-20° F + |
SAE 15W-40 |
0° F + |
SAE 15W-50 |
0° F + |
SAE 20W-40 |
0° F + |
SAE 20W-50 |
0° F + |
SAE 10W |
-20° F to 32° F |
SAE 20W |
0° F to 60° F |
SAE 30W |
32° F to 90° F |
SAE 40W |
75° F + |
SAE 50W |
75° F + |