3948072 Oil Pump Assembly for Hyundai R300LC & Komatsu PC300

3948072 Oil Pump for Hyundai R300LC and Komatsu PC300

The 3948072 / 3966840 engine oil pump is supplied for heavy equipment engine lubrication system repair. It is commonly searched for Hyundai R300LC, Hyundai R320LC-7, Komatsu PC300 and related equipment using Cummins 6CT, 6CTA, ISC or QSC 8.3L engine references.

This page focuses on 3948072 and 3966840 as the main part numbers. 3942723, 3950005, 3991123, 4941464 and 4983588 can be used as checking references in Cummins 8.3L and 8.9L oil pump listings. Final fitment should be confirmed by the old oil pump number, engine model, gear side, mounting face, oil passage layout and machine information before ordering.

Engine Application: Cummins 6CT 8.3L and ISL 8.9L References

For this product page, the engine direction is more important than the machine model alone. 3948072 and 3966840 are mainly associated with Cummins C-series oil pump applications, including 6CT, 6CTA, ISC and QSC 8.3L references. Some market listings also connect the same oil pump direction with ISL, QSL or L8.9 engine references.

This page should not be written like a Cummins 5.9L oil pump page. The search focus here is the larger 8.3L / 8.9L oil pump direction, which is different from smaller Cummins 6BT 5.9L oil pump pages such as 4935792 or 3926203.

If the buyer only provides a machine model, ask for the engine nameplate and old oil pump photos. If the buyer only provides an engine model, confirm the old pump number, pump body shape and gear-side details before quotation.

Machine Reference for Hyundai and Komatsu Equipment

The main machine references for this page are Hyundai R300LC and Komatsu PC300. Public market references also mention Hyundai R300LC-9S, R320LC-7, R330LC-9S and R360LC-7 when the equipment uses a Cummins 6CT engine direction.

Komatsu PC300 and PC300-7 can be kept as application references because buyers may search this oil pump by machine model during repair. However, for Komatsu applications, the old oil pump number and engine information must be checked before shipment, especially when the machine uses Komatsu engine model naming or has previous repair history.

For accurate ordering, compare the removed oil pump with the replacement unit before shipment. Photos of the old pump number, gear side, mounting face, oil passage area, pump housing and engine nameplate are useful for confirmation.

Part Number and Cross Reference Notes

3948072 and 3966840 are the main part number directions for this product page. Both should stay visible in the product title, top parameters, image ALT text and first paragraph because buyers may search either number.

3942723, 3950005, 3991123, 4941464 and 4983588 may appear as cross reference or replacement numbers in Cummins 8.3L / 8.9L oil pump listings. These references are useful for matching, but the removed pump and engine information should still be checked before ordering.

I do not recommend adding every nearby Cummins oil pump number into the top parameter area. Too many numbers can dilute the 3948072 / 3966840 page signal and may increase wrong-part inquiries from buyers searching for a different Cummins engine family.

How to Confirm the Correct 3948072 Oil Pump

Cummins 8.3L and 8.9L oil pumps can look similar, but the gear design, body thickness, mounting face and oil passage layout may differ. Before ordering, compare the removed pump carefully.

• Confirm whether the old oil pump number is 3948072, 3966840 or a listed checking reference.

• Check whether the engine model is Cummins 6CT, 6CTA, ISC, QSC, ISL or QSL series.

• Compare the gear side, pump housing and mounting face.

• Check oil inlet, oil outlet and internal oil passage positions.

• Confirm gasket surface, bolt hole pattern and timing gear fitment area.

• Send machine model, engine nameplate and old oil pump photos before quotation if you are not sure.

Why This Page Should Focus on 8.3L and 8.9L Engines

The 3948072 / 3966840 oil pump direction is different from many smaller engine oil pumps used on compact excavators. Buyers for this page are more likely to be repairing medium and heavy equipment engines, where oil pressure stability is critical for bearings, turbocharger lubrication and long-hour jobsite operation.

For repair shops, the old pump photos should include both sides of the pump, not only the front housing. The gear-side view, bolt hole layout and oil passage area are important because similar-looking oil pumps may belong to different Cummins engine versions.

This is also why the page should not become a general Cummins oil pump catalog. Keeping the content focused on 3948072, 3966840, Cummins 6CT / ISC 8.3L and ISL / QSL 8.9L helps both buyers and search engines understand the product clearly.

Common Oil Pump Failure Symptoms

An engine oil pump may need replacement when the machine shows low oil pressure, oil pressure warning, unstable lubrication after startup, abnormal bearing noise, engine overheating, metal particles in oil or serious internal engine wear.

On Hyundai R300LC, R320LC and Komatsu PC300 class machines, oil pump problems may appear after long working hours, poor maintenance, oil sludge buildup, overheating or internal bearing wear. The oil pump should be checked together with the complete lubrication system.

These symptoms are not always caused by the oil pump itself. Blocked oil passages, dirty engine oil, worn bearings, damaged pickup tube, clogged strainer, pressure relief valve problems or incorrect engine oil viscosity can create similar problems.

Troubleshooting Before Replacement

Before ordering a 3948072 / 3966840 replacement oil pump, check the lubrication system and the real reason for low oil pressure. This helps avoid replacing the pump when the root cause is oil contamination, bearing wear or blockage.

• Check engine oil level, oil grade and oil contamination.

• Inspect the oil filter, oil strainer and pickup tube condition.

• Check whether sludge or metal particles are present in the oil pan.

• Inspect crankshaft bearings, camshaft bearings and related lubrication surfaces.

• Confirm whether the pressure relief valve is stuck, worn or contaminated.

• Clean the oil circuit if the old pump failed due to contamination, sludge or engine wear.

Installation and Maintenance Notes

Before installation, clean the timing gear area, mounting surface and oil passages. Compare the replacement pump with the removed unit, including gear position, pump body shape, bolt holes and gasket surface.

Use a proper gasket or sealing method according to the engine repair requirement. After installation, check oil pressure during startup and confirm that oil circulates normally before putting the engine under load.

For longer service life, use clean engine oil, replace filters on time and avoid running the engine with low oil pressure. If the previous failure was caused by sludge, bearing wear or contamination, those causes should be corrected during repair.

Buying Notes for Repair Shops and Parts Distributors

For repair shops, this 3948072 / 3966840 engine oil pump is suitable for Cummins 8.3L and 8.9L engine lubrication repair when the old pump is worn, damaged or unable to maintain stable oil pressure.

For parts distributors, it can be supplied as a replacement oil pump reference for Hyundai R300LC, Hyundai R320LC, Komatsu PC300 and other equipment using Cummins C-series engine applications. Topvelsun supports small repair orders and bulk inquiries. Please send the required quantity, old pump number, engine model, machine model and photos of the old oil pump from multiple angles.

FAQ

What is the main product on this page?

This page is for the 3948072 / 3966840 engine oil pump used for Cummins 6CT, 6CTA, ISC, QSC, ISL and QSL engine lubrication system repair.

Can 3966840 be used as a reference for 3948072?

Yes. 3966840 appears together with 3948072 in Cummins 8.3L and 8.9L oil pump references. Final fitment should still be confirmed by the old oil pump and engine information.

What cross references can be checked?

Common checking references include 3942723, 3950005, 3991123, 4941464 and 4983588. These numbers are useful for matching, but the removed pump and engine model should still be verified before shipment.

Which engine models are the main references?

The main engine references are Cummins 6CT, 6CTA, ISC and QSC 8.3L. ISL and QSL 8.9L may also appear in related references, but the old oil pump should be checked before ordering.

Which machine models can be used as references?

The main machine references are Hyundai R300LC and Komatsu PC300. Other Hyundai references such as R320LC-7, R330LC-9S and R360LC-7 may also appear when the machine uses a Cummins 6CT engine direction.

Is this the same as a Cummins 6BT 5.9L oil pump?

No. This page should be positioned for Cummins 8.3L and 8.9L oil pump references. Cummins 6BT 5.9L oil pump pages should be handled separately to avoid wrong-part matching.

What should I check before ordering?

Please check the old oil pump number, engine model, gear side, pump body shape, mounting face, bolt hole pattern and oil passage position. Clear photos of the removed pump are recommended.