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Why Diesel Pro Power Charges a Core Charge for Rebuilt Oil Pumps on Detroit Diesel 2-Stroke Engines
Detroit Diesel’s 2-stroke engines — including the 53-Series, 71-Series, 92-Series, and 149-Series — have earned a legendary reputation for toughness, simplicity, and rebuildability. Their continued survival today, decades after most were manufactured, is possible because key components can still be remanufactured to original Detroit Diesel specifications. One of the most important items in that ecosystem is the engine oil pump.
When customers purchase a rebuilt oil pump for a Detroit Diesel two-cycle engine from Diesel Pro Power, they will see a core charge added to the order. This practice is not a penalty nor an extra fee — it is a critical system that ensures rebuilt pumps remain available, affordable, and built to OEM standards.
This article explains in detail why core charges exist for Detroit Diesel oil pumps, how the system works, what parts the core helps recycle, and why returning your old pump ultimately benefits every 2-stroke Detroit owner.
See Our Catalog Of Rebuilt Oil Pumps For Detroit Diesel Engines
Use Our Return Of Goods Authorization Form To Return Your Core Oil Pump
Oil Pump & Related Components for Detroit Diesel 6V71 Non – Turbo Engine
Oil Pump & Related Components for Detroit Diesel 6V71 Turbo Engine
Oil Pump & Related Components for Detroit Diesel 8V71 Non – Turbo Engine
Oil Pump & Related Components for Detroit Diesel 8V71 Turbo Engine
The Oil Pump: A Critical Lifeline in a Detroit Diesel 2-Stroke Engine
Detroit Diesel’s 2-stroke engines rely heavily on oil pressure to survive. Unlike four-stroke designs, Detroit 2-strokes use pressurized oil to:
- Lubricate crankshaft and camshaft bearings
- Feed the blower drive gears
- Cool piston undersides
- Lubricate rocker arms and injector followers
- Maintain clean oil circulation through high-RPM operation
Any drop in oil pressure can quickly lead to catastrophic damage. The oil pump is the heart of that entire system.
The challenge is that new, OEM Detroit Diesel oil pump housings for 71-Series, 92-Series, and 53-Series engines are no longer produced in large quantities. The solution — and the reason core charges exist — is remanufacturing.
What Is a Core Charge?
A core charge is a refundable deposit added to the sale of a rebuilt oil pump. When customers return their old (used) pump, Diesel Pro Power refunds this deposit.
In simple terms:
You pay the core charge → return your old pump → receive the core refund.
If the old pump is not returned, the deposit is kept to help cover the cost of sourcing a replacement core.
This system exists because the housing of the oil pump is rebuildable, and its return is essential for continued parts availability.
Reason #1: Core Charges Ensure a Supply of Rebuildable OEM Pump Housings
Detroit Diesel 2-stroke engines have not been manufactured in decades. That means the supply of OEM oil pump housings is limited. The aluminum or cast-iron housings are durable and can often be remachined to like-new condition — but only if Diesel Pro Power receives them back.
A returned oil pump core provides:
- An OEM housing (the most valuable part)
- Rebuildable internal pockets
- Reusable pressure-relief components
- Machinable gear surfaces
- Correct Detroit-spec mounting geometry
These are not easily reproduced aftermarket. The tolerances required for Detroit 2-stroke oil pumps are extremely tight — often within thousandths of an inch.
Without customer-returned cores, it would eventually become impossible to offer rebuilt pumps at all.
Reason #2: Core Returns Keep Rebuilt Pumps Affordable
If Diesel Pro Power had to manufacture brand-new housings from scratch, the cost of a rebuilt oil pump would be significantly higher — likely several times the current retail price.
By recycling cores:
- The most expensive part of the pump (the housing) is reused
- Only worn internal parts need replacement
- Machining operations become efficient and repeatable
- Costs stay stable even as engines age
- Customers get OEM-grade quality without new-manufacture prices
The core charge ensures that these rebuildable housings come back instead of ending up scrapped or forgotten in storage sheds and engine rooms.
Reason #3: Rebuilt Pumps Rely on Inspectable, Reusable Components
When a core is returned, it undergoes a strict inspection. Diesel Pro Power evaluates:
- The housing for cracks, scoring, or warpage
- Internal oil galleries
- Gear pockets and wear surfaces
- Pressure-relief valve bore condition
- Shaft support alignment
If the housing passes inspection, it is fully remanufactured. If not, it is scrapped and replaced with another housing — a cost the core charge helps offset.
Returning your core ensures there is always a flow of rebuildable housings to choose from.
Reason #4: The Core Charge Filters Out Unusable Cores
Not every oil pump is rebuildable. Some are damaged from:
- Low-oil conditions
- Overheating
- Cavitation
- Corrosion
- Cracked housings
- Broken gears
The core charge provides a financial incentive for customers to return pumps in rebuildable condition. If the pump is too damaged to rebuild, Diesel Pro Power must:
- source another core
- absorb the cost of the bad core
- maintain inventory for the next customer
The core charge helps balance this risk.
Reason #5: The Core Model Helps Keep Detroit 2-Strokes Alive
The continued availability of rebuilt components is what allows Detroit Diesel engines — many over 40 or 50 years old — to keep operating reliably.
Returning cores helps ensure that:
- marine fleets
- fishing boats
- head boats
- tug operators
- generator systems
- construction equipment
- classic truck owners
can continue to maintain their engines for decades to come.
Without the core-return cycle, it would become significantly harder to support aging Detroit 2-strokes — especially the 6-71, 8V71, 8V92, 12V71, 16V92, and similar models whose production ended years ago.
Reason #6: Remanufactured Pumps Must Meet OEM Tolerances
Detroit Diesel oil pumps have extremely tight tolerances. The clearances between internal gears and the housing are critical for:
- maintaining hot-idle pressure
- supporting high-RPM lubrication
- regulating oil flow to piston cooling jets
- preventing pressure bleed-off
- supplying the blower drive with lubrication
Remanufacturing an oil pump requires:
- resurfacing end plates
- restoring proper gear-to-housing clearance
- replacing shafts, gears, or relief valves
- reestablishing the exact Detroit Diesel specifications
OEM housings are the best foundation for this process. Aftermarket housings are often inconsistent, out of tolerance, or made from softer alloy that fails prematurely.
Cores ensure consistent OEM geometry.
How the Core Charge Benefits YOU, the Customer
Even though it appears as an upfront cost, returning your core directly benefits you:
You pay less overall.
Returning a rebuildable core drops the total cost of the pump by the amount of the core refund.
You get a pump rebuilt from OEM Detroit components.
Better fit, better durability, longer service life.
You help maintain future parts availability.
Every core returned becomes part of the supply chain that keeps Detroit 2-strokes serviceable.
You avoid the risk of low-quality aftermarket alternatives.
Core recycling keeps true Detroit Diesel housings in circulation.
You support environmentally responsible remanufacturing.
Less metal waste, less machining, less energy used.
Final Thoughts: The Core Charge Keeps Detroit 2-Strokes Running
The core charge on rebuilt Detroit Diesel 2-stroke oil pumps is not just a business policy — it is the foundation of keeping these engines alive decades past their original production run.
By returning your core, you help ensure that:
- OEM housings remain available
- Rebuilt pumps stay affordable
- Engines remain serviceable
- The Detroit Diesel 2-stroke legacy continues
It is a system that benefits the customer, the supplier, and the entire Detroit Diesel community.
