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2020 GM Duramax 2500HD–3500HD Diesel Engine 6.6L

2020 Duramax 6.6L Diesel Engine

Used Engines Inventory

Reman Engines Inventory

Diesel Engines Inventory

High-output L5P 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

High-output L5P long block replacement

The 2020 Duramax 6.6L L5P long block is engineered for exceptional power delivery, high-pressure fueling, and robust towing performance in GM HD trucks. Houston Engines supplies both remanufactured and thoroughly tested used units built to withstand heavy workloads. Blocks undergo crack inspection, surface machining, and lubrication system verification. Cylinder heads are reconditioned and pressure-tested, ensuring consistent combustion and sealing. Updated pistons, rings, and bearings restore performance and reliability, making this long block ideal for heavy towing, commercial fleets, and long-haul drivers depending on stable diesel output.

Reman L5P engines receive full machining including torque-plate honing, crankshaft refinishing, deck resurfacing, and balanced rotating assemblies.

Cylinder heads are rebuilt with new valve components engineered for high-cylinder-pressure operation. All gaskets, bearings, seals, and pistons are replaced to restore OEM integrity and reduce heat-related wear. These remanufactured engine units undergo controlled testing to confirm oil pressure stability and consistent compression, supporting GM diesel performance for demanding applications.

Used L5P engines complete compression, leak-down, and borescope testing. External gaskets are refreshed, and accessories are inspected for compatibility. Houston Engines ensures that both reman and used long blocks meet the rigorous demands of modern Duramax performance, keeping Silverado 2500 diesel engine and Sierra 3500HD engine owners reliable for towing, hauling, and commercial use. These verified procedures offer long-term value for anyone seeking a dependable used engine or a fully reman L5P Duramax replacement.

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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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Testing Procedures and Warranty Coverage Explained

Each 2020 L5P long block completes compression verification, oil pressure assessment, and cylinder balance testing. Hot-run documentation is provided when applicable and tied to the unit’s serial number for proper tracking and verification that supports 6.6L warranty validation.

Reman long blocks include extended warranty coverage; used L5P engine units include standard limited coverage with required installation documentation. Proper installation steps help preserve warranty protections offered by Houston Engines.

Prime the oil system, fill with break-in oil, and cycle the engine through controlled warm-up intervals to ensure proper lubrication and heat distribution.

Replace coolant, filters, belts, and hoses as part of installation. Confirm intercoolers, EGR systems, and turbocharger housings are free of carbon buildup or debris. These steps help ensure strong GM diesel performance during the initial L5P break-in and prevent early wear.

Monitor oil pressure, EGTs, and coolant temps throughout the break-in period to verify stable operation under varying loads. Proper installation and fluid service help ensure long-term ring sealing, stable idle, and consistent L5P towing performance. These steps protect warranty coverage and maintain the engine’s longevity under sustained load, supporting both commercial operators and daily drivers who depend on reliable GM diesel performance.

Engine Fitment and Vehicle Compatibility Guide

Fits 2020 Chevrolet Silverado 2500HD/3500HD and GMC Sierra 2500HD/3500HD equipped with the 6.6L L5P Duramax. Confirm VIN, emissions package, and transmission pairing before ordering to ensure proper matching of your diesel engine components and accurate L5P long block selection.

Houston Engines validates casting numbers, accessory patterns, and oiling system configuration before shipping. This ensures accurate fitment for both remanufactured engine and used engine orders, minimizing installation delays.

Contact Houston Engines for installation support, torque spec resources, and warranty activation details. Our team coordinates freight, core returns, and technical guidance to ensure efficient replacements. For any questions or to order, simply contact us for fast assistance, and our experts will provide the reliable support you need from purchase to installation.

Freight process and core return

Duramax engines ship on reinforced pallets with banding, padding, and moisture protection. Lift-gate and dock delivery services are available nationwide. This secure Duramax freight process ensures safe transport for both reman L5P Duramax and used L5P engine shipments.

Cores must be drained and returned in the original crate using the supplied RMA and shipping documents. Secure the engine with straps to prevent shifting during transport. Returning the core promptly keeps the process smooth and maintains eligibility for full credit.

Credit is issued after inspection. Damaged, incomplete, or contaminated cores may reduce credit value. Review the core checklist thoroughly before returning your unit to ensure maximum refund and a smooth experience with Houston Engines.

Frequently Asked Questions (FAQs)

Frequently Asked Questions (FAQ)

What vehicles use the 2020 Duramax 6.6L engine?

It fits 2020 Silverado 2500/3500 and Sierra 2500HD/3500HD models using the L5P long block diesel engine.

Is the 2020 Duramax 6.6L engine reliable?

Yes, when properly maintained, it provides strong towing power, stable performance, and dependable GM diesel performance.

Does Houston Engines offer warranty coverage?

Each engine includes a Cummins warranty, with extended coverage for reman units and standard limited coverage for used ones.

What is included in a reman L5P Duramax?

Reman units include new pistons, rings, bearings, resurfaced heads, machining, and full component replacement.

Are used L5P engines tested before shipping?

Yes, they undergo compression testing, leak-down verification, and borescope inspection.

How does Houston Engines handle freight?

Engines ship on secure pallets with moisture protection and nationwide lift-gate or dock delivery options.

What should be replaced during installation?

Break-in oil, coolant, belts, filters, and gaskets should be replaced to support proper L5P break-in.

Can original parts be reused with this engine?

Yes. Many accessories, sensors, brackets, and the turbocharger typically transfer from your original engine.

How can I maintain long engine life?

Monitor oil pressure, maintain cooling systems, follow break-in steps, and keep service intervals consistent.

How do I order a 2020 Duramax 6.6L engine?

Simply contact us at Houston Engines for pricing, fitment checks, freight details, and warranty options.

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.