Isuzu 4.8L Oil Change Guide

Isuzu NPR/NPQ 4.8L 4HE1 Oil Selection & Oil Change Procedures

Isuzu recommends replacing the engine oil and oil filter every 6,500 miles or 12 months (whichever comes first) on all 4.8L equipped NPR/NPQ models. More frequent oil changes are advised if vehicles are subjected to extended periods of idling or operated in extremely hot/cold climates.

Isuzu 4.8L 4HE1 Oil Change Parts List & Oil Selection

We highly recommend a full synthetic diesel engine oil due to its superior lubrication properties and resilience to mechanical, chemical, and thermal breakdown. Amsoil's Heavy Duty Diesel and Signature Series Max Duty Diesel product lines are our preferred full synthetic diesel motor oils for engines old or new.


Spec/Part Number(s)


Engine oil

SAE 15W-40 engine oil
(see chart below for all suitable viscosities)

14.8 quart capacity (14.0 liters) w/ filter change
Recommend Amsoil Heavy Duty full synthetic diesel oil

Engine oil filter

ACDelco PF1702
Wix 57521
Baldwin BD7169

Fill filter with engine oil before installation to prevent dry start

Oil pan drain plug

GM 11569943

M14 x 1.50 threads

Oil fill cap

Stant 10101

Replace as necessary

Isuzu 4.8L 4HE1 Oil Viscosity & Oil Selection

Note that many of the 4HE1's acceptable oil grades are relatively impractical due to limited operating temperature ranges; SAE 15W-40, 10W-40, and 10W-30 oils are common grades that suit the needs of most driving conditions. Multi-grade engine oils are preferred to single or "straight weight" oils under most circumstances, however they are a suitable option so long as the selected oil is operated within the corresponding ambient temperature range. Isuzu calls for an API CD category engine oil for all 4HE1 engines; this specification is long obsolete, but any diesel engine oil with a modern API rating will suffice.

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 +


32° F to 90° F

Source: 1999 - 2002 Isuzu NPR/NQR service manuals. Select viscosities omitted due to redundancies, limited operating temperature range, impractical, and/or otherwise obsolete.

Isuzu 4.8L (4HE1) Oil Change Procedures

Click any thumbnail to view fullsize, detailed image

engine oil pan drain plug location

• Place a suitable container beneath the engine oil pan (minimum 15 quart capacity).

engine oil draining

• Remove the engine oil pan drain plug (typically requires a 17 mm socket/wrench).

• Allow the engine oil to drain completely.

• Examine the condition of the oil pan drain plug and gasket; replace as necessary.

• Reinstall the oil pan drain plug; snug, but do not overtighten.

engine oil filter location

• Reposition the oil drain container beneath the oil filter located on the drivers side of the engine block.

• Remove the engine oil filter and allow any residual oil to drain.

Oil filter removed

• Verify that the oil filter gasket was removed with the filter and is not stuck to the oil filter mount.

• Carefully clean the oil filter mount with a clean, lint free cloth/shop rag.

lubricating engine oil filter gasket

• Fill the new oil filter with roughly (1) quart of clean engine oil. Do not overfill; this step simply limits the effects of a dry start following the oil change.

• Lubricate the new oil filter gasket with clean engine oil.

New oil filter installed

• Install the replacement oil filter. Snug down tightly by hand; do not attempt to tighten the filter using an oil filter wrench, as overtightening the filter may damage and/or compromise the gasket seal.

filling crankcase with engine oil

• Fill the crankcase with new engine oil. The amount of oil added to the crankcase will be equal to 14.8 quarts MINUS the quantity added to the replacement oil filter (i.e. if the oil filter held 1 quart of oil, 13.8 quarts would be added to the crankcase through the engine oil fill). The engine oil fill is located on the valve cover near the front of the engine. Verify engine oil level on dipstick prior to starting.

• Start the engine and check for leaks. Shutdown engine and verify engine oil level after allowing the oil to drain back into the crankcase for several minutes.