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1999 Cummins ISB 3.9L Diesel Engine

1999 Cummins 3.9L Diesel Engine

Used Engines Inventory

Reman Engines Inventory

Diesel Engines Inventory

Reliable 4-cylinder ISB long block replacement

The 2012 Ford Powerstroke 6.7L Diesel Engine is a robust choice for heavy-duty applications, found in the 2012 Ford F250, F350, and F550 models. This turbocharged V8 engine delivers significant torque and horsepower, making it ideal for towing and hauling. Its design ensures both performance and efficiency, with a reputation for reliability and durability. Whether for work or recreation, the 6.7L Powerstroke handles demanding tasks with ease. For more details on its performance and specs, visit our 2012 F250 diesel engine page.

Diesel Engine

Reliable 4-cylinder ISB long block replacement

The 1999 Cummins 3.9L diesel long block is ideal for light-duty trucks, step vans, and medium-duty equipment. Houston Engines provides both used and fully remanufactured engines built to original Cummins specifications for dependable performance. Each engine is thoroughly cleaned internally, checked for cracks, and compression-tested to ensure balanced operation. Bearings, pistons, and seals meet or exceed OE standards. Whether you need a single replacement or a complete fleet rebuild, the ISB 3.9 diesel delivers efficient power, consistent performance, and proven Cummins reliability for daily and industrial use.

Reman engines receive complete disassembly, machining, and cleaning before reassembly to restore factory-level performance. Processes such as torque-plate honing, deck resurfacing, and crankshaft grinding ensure precision tolerances.

New pistons, rings, and bearings are installed, while cylinder heads are pressure-tested, resurfaced, and fitted with new valve guides and seals. Every fastener is torqued to factory specification, and oil galleries are ultrasonically cleaned to maintain proper flow, ensuring smooth operation, reliable compression, and consistent engine longevity.

Used 3.9L Cummins long blocks are carefully selected from trusted donor engines to guarantee quality. Each engine undergoes leak-down and compression verification, visual inspection, and thorough cleaning for reuse. Seals and gaskets are replaced as needed, and detailed build records are documented for full traceability. Whether choosing a reman Cummins 3.9L or a used Cummins 3.9L, both options provide smooth idle, clean emissions, and extended service life for dependable daily or commercial performance.

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Are you in the market for a used engine to get your vehicle back up and running? Look no further than Houston Engines. We offer a wide selection of high-quality, used engines at affordable prices. We pride ourselves on our commitment to customer satisfaction and provide a hassle-free shopping experience for all our clients.

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Quality testing and warranty terms

Every 1999 Cummins long block is compression-verified and bench-tested where possible to ensure reliable performance. Test results are recorded by serial number, providing accuracy, traceability, and peace of mind for each engine.

Used engines include limited coverage, while reman Cummins 3.9L units feature extended Cummins 3.9 warranty protection. Detailed maintenance guidelines are provided at purchase to help maintain warranty compliance and ensure long-lasting, dependable performance for both daily and commercial applications.

Before startup, always prime the oil system and use the recommended break-in oil to protect internal components during initial operation.

Perform early oil and filter changes according to manufacturer guidelines, and flush the fuel and cooling systems to remove contaminants and ensure clean flow. Inspect all hoses, fittings, and connections for leaks, blockages, or damage to maintain proper circulation and prevent premature wear on your ISB engine rebuild.

If reusing accessories or the turbocharger, clean them thoroughly to eliminate debris, oil residue, or carbon buildup that could compromise engine performance. Following these installation and break-in steps helps achieve balanced compression, stable performance, and consistent operation. Proper attention to early maintenance and component inspection maximizes reliability and extends the service life of your ISB engine rebuild, ensuring it delivers dependable power for both daily and demanding applications.

Fitment and application details

This 3.9L ISB long block fits 1999 light-duty trucks, industrial equipment, and select vocational vehicles. Always confirm the engine family number, emissions calibration, and accessory configuration before placing your order to ensure proper fit and performance.

The Houston Engines team can verify compatibility across multiple models and provide guidance on conversion or retrofit applications. Their expertise ensures your 3.9L ISB installation is accurate, efficient, and fully optimized for reliable operation in a variety of vehicles.

Houston Engines provides start-up documentation, torque specs, and comprehensive installation guidance to ensure proper engine setup. Contact the team to review shipping timelines, core handling procedures, and technical details before placing your order. This proactive approach helps streamline the installation process, prevent delays, and ensures a seamless experience, allowing your Cummins engine to operate reliably and efficiently from the start.

Freight packaging and core return

All used engine and remanufactured engine orders are securely packaged with reinforced corner protection and steel strapping to prevent damage during transit. Freight delivery options include lift-gate and dock service, making unloading easy and safe for any facility. Proper packaging and handling ensure that your engine arrives in optimal condition, ready for installation or storage.

Before returning your core, drain all fluids completely and secure it in the original crate. Attach the supplied RMA and BOL paperwork, and schedule pickup promptly to avoid delays or deductions in core value. Following these steps ensures your return is processed efficiently and accurately.

Cores are inspected immediately upon arrival, and refunds are issued quickly after verification. Excessive damage or missing major components can reduce the refund amount, so carefully review the provided checklist to ensure a smooth return process and full core credit.

Frequently Asked Questions (FAQs)

Frequently Asked Questions (FAQ)

What vehicles use the 1999 Cummins 3.9L engine?

The ISB 3.9 diesel was used in light-duty trucks, step vans, and small industrial machines.

Are these engines compression-tested?

Yes, every used Cummins 3.9L and reman Cummins 3.9L engine is compression-verified before shipping.

What warranty options are available?

Used units include limited protection, while reman Cummins 3.9 warranty plans offer extended coverage.

Do you ship nationwide?

Yes, Cummins 3.9 shipping is available throughout the U.S. via reliable freight carriers.

Can you help confirm engine fitment?

Absolutely. Contact us with your VIN or engine family number for accurate fitment verification.

What is included in the 1999 Cummins long block?

Each long block includes the block, head, crankshaft, rods, pistons, and internal components—ready for accessories.

How should I prepare the engine for installation?

Prime oil passages, replace filters, and follow supplied startup and ISB engine rebuild instructions.

Are reman engines completely rebuilt?

Yes, remanufactured engines are fully machined, fitted with new internals, and assembled to OE specs.

What makes the Cummins 4BT engine reliable?

Its simple design, low-maintenance operation, and proven Cummins reliability make it a top performer.

How do I start an order or get a quote?

Visit HoustonEngines.com or contact us directly to request pricing and shipping details.

Why Buy From Us?

We strive to be the ultimate destination for recycled auto parts. With access to a vast inventory and exclusive parts network, we offer millions of quality parts. We specialize in used engines and transmissions with new stock weekly. Our commitment to quality means that you can trust that you're getting the best possible part for your vehicle.