Used Chevrolet Silverado 2500HD Engines
Used, remanufactured and rebuilt engines for the 1999-to-present Chevrolet Silverado 2500 and 2500HD — tested before they ship and covered by warranty. Tell us your truck and we’ll match the exact engine.
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Engine Options
Which engine does your Silverado 2500HD have?
The Silverado 2500 arrived for 1999 as a light-duty three-quarter-ton with the 5.3L or 6.0L Vortec V8. The 2500HD followed for 2001 with the 6.0L, the 8.1L big-block and the first 6.6L Duramax diesel, and the choice has been gas or Duramax ever since. The gas engine went from the LQ4 to the LY6 and L96, then to the direct-injected 6.6L L8T for 2020 and its update, the L8S, for 2027. The 6.6L Duramax came in six versions — LB7, LLY, LBZ, LMM, LML and L5P — each with its own injection and emissions equipment, and for 2027 the 8.3L L6P Duramax replaced it.
Through 2000 GM also kept selling the older C/K-body 2500, a different truck with different engines, so a 1999 or 2000 model can be either. Two of the Duramax changes and the 2007 change of body happened mid-year. The table below gives the usual split, and we confirm the exact engine from the VIN and build date.
| Engine | Code | Notes |
|---|---|---|
| 5.3L V8 Vortec 5300 | Code: LM7 | Two-wheel-drive 7,200-lb trucks only. |
| 6.0L V8 Vortec 6000 | Code: LQ4 | Every 8,600-lb truck; cast-iron heads in these two years. |
| Engine | Code | Notes |
|---|---|---|
| 6.0L V8 Vortec 6000 | Code: LQ4 | Standard gas V8; iron block, aluminum heads. |
| 8.1L V8 Vortec 8100 | Code: L18 | Big-block option through the 2007 Classic. |
| 6.6L Duramax V8 turbodiesel | Code: LB7 | 2001 to early 2004; 300 hp/520 lb-ft. |
| 6.6L Duramax V8 turbodiesel | Code: LLY | Mid-2004 to 2005; 310 hp/605 lb-ft. |
| 6.6L Duramax V8 turbodiesel | Code: LBZ | 2006 and the 2007 Classic; 360 hp/650 lb-ft. |
| Engine | Code | Notes |
|---|---|---|
| 6.0L V8 Vortec 6000 | Code: LY6 | 2007.5–2009; iron block, variable valve timing. |
| 6.0L V8 Vortec 6000, flex-fuel | Code: L96 | 2010–2014; 360 hp/380 lb-ft. |
| 6.6L Duramax V8 turbodiesel | Code: LMM | 2007.5–2010; adds a particulate filter; 365 hp/660 lb-ft. |
| 6.6L Duramax V8 turbodiesel | Code: LML | 2011–2014; DEF and the Bosch CP4.2 pump; 397 hp/765 lb-ft. |
| Engine | Code | Notes |
|---|---|---|
| 6.0L V8 Vortec 6000, flex-fuel | Code: L96 | Standard gas engine, all years. |
| 6.6L Duramax V8 turbodiesel | Code: LML | 2015–2016. |
| 6.6L Duramax V8 turbodiesel | Code: L5P | 2017–2019; Denso HP4 pump. 445 hp/910 lb-ft. |
| Engine | Code | Notes |
|---|---|---|
| 6.6L V8 gas | Code: L8T | Iron block, direct injection, no cylinder deactivation; 401 hp/464 lb-ft. |
| 6.6L Duramax V8 turbodiesel | Code: L5P | 445 hp/910 lb-ft; uprated to 470 hp/975 lb-ft for 2024. |
| Engine | Code | Notes |
|---|---|---|
| 6.6L V8 gas | Code: L8S | Update of the L8T; 412 hp/472 lb-ft. |
| 8.3L Duramax V8 turbodiesel | Code: L6P | Replaced the 6.6L Duramax; 555 hp/1,230 lb-ft. |
Not sure which one is yours? Request a quote and we’ll work it out from your VIN.
Before You Order
What to check before you order
1999–2000: check the weight rating
The light-duty 2500 of these years was rated at 7,200 lb or 8,600 lb GVWR, and the 7,200-lb rating was offered on two-wheel-drive trucks only. The 5.3L went only in the 7,200-lb trucks, and every 8,600-lb truck has the 6.0L. The rating is printed on the label in the driver’s door jamb.
Old body or new body
A 1999–2000 crew cab, or a 2500 of those years with the 5.7L, 7.4L or 6.5L diesel, is the older C/K-body truck rather than the new Silverado. Its engines do not fit this truck, so tell us which you have.
Which Duramax
Six 6.6L versions, two of them changing mid-year: LB7 to early 2004, LLY from mid-2004, LBZ for 2006 and the 2007 Classic, LMM from mid-2007, LML from 2011, L5P from 2017. The 8.3L L6P took over for 2027. Each has its own injection and emissions equipment, so we match the code and build date, not just the model year.
Two 2007 trucks
The 2007 Classic is the old GMT800 with the LQ4, 8.1L or LBZ; the 2007.5 is the new GMT900 with the LY6 or LMM. The VIN tells us which you have.
Three 6.0L gas engines
The LQ4, LY6 and L96 share a displacement and an iron block, but the 1999–2000 LQ4 also has iron heads, the LY6 added variable valve timing and the L96 is flex-fuel. They are different engines; match the code.
Have your VIN ready
With the VIN we can confirm the engine, build date and model year before we quote, which avoids ordering the wrong Duramax.
Common Problems
Common Silverado 2500HD engine problems
Injector failure — LB7 Duramax, 2001–2004
The injectors sit under the valve covers and crack or erode, putting fuel in the oil and causing hard starts and smoke; the whole set is normally replaced. GM once extended the injector warranty on these engines, but that coverage has expired.
Overheating when towing — LLY Duramax, 2004–2005
The LLY runs hot under sustained heavy load, such as towing up long grades in summer heat, and repeated overheating can lead to a blown head gasket.
CP4 fuel-pump failure — LML Duramax, 2011–2016
The Bosch CP4.2 high-pressure pump can destroy itself and send metal through the whole fuel system, which then means replacing the injectors, rails and lines along with the pump.
Manifold bolts and knock sensors — 5.3L and 6.0L gas, 1999–2007
Broken exhaust-manifold bolts give a tick on cold starts, and the knock sensors under the intake manifold, or their wiring, fail and set knock codes. Both are repairs to the engine in the truck, not a reason to replace it.
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FAQ
Silverado 2500HD engine questions, answered
Which Duramax does my Silverado 2500HD have?
By model year: LB7 for 2001 to early 2004, LLY for mid-2004 to 2005, LBZ for 2006 and the 2007 Classic, LMM for 2007.5–2010, LML for 2011–2016, L5P for 2017–2026 and the 8.3L L6P from 2027. Because two of the changes were mid-year, send us your VIN and we’ll confirm from the build.
Was there a Duramax in the 1999–2000 Silverado 2500?
No. The Duramax arrived with the 2500HD for 2001, so a 1999–2000 Silverado 2500 has the 5.3L or 6.0L gas V8. A diesel three-quarter-ton from those years is the older C/K-body 2500 with the 6.5L turbodiesel.
Will an engine from a GMC Sierra 2500HD fit?
GM builds the Sierra 2500HD with the same engines, so a unit of the same year, code and build is the same part. Send us your VIN and we’ll confirm the match.
Is there a recall or extended coverage on my engine?
Check before you buy: run your VIN at nhtsa.gov/recalls and ask a Chevrolet dealer about open recalls and special coverage. The extended injector coverage GM gave the LB7 has expired, so a failed LB7 injector set is now a repair the owner pays for.
Is the engine covered by a warranty?
Yes. Every engine we sell is covered by warranty, and extended cover is available at extra cost. The full terms are in our Warranty Policy.
Ready to replace your Silverado 2500HD engine?
Tell us the year and have your VIN to hand — a specialist will confirm the right unit and send you a quote.
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