The GM LBZ is a 6,599 cc, 90° V8 turbo‑diesel engine produced for the 2006 and 2007 model years. It features a robust Bosch common‑rail direct injection system and a variable‑geometry turbocharger (VGT), delivering 231 kW (313 PS) and 609 Nm of torque. Its forged steel connecting rods and revised cylinder head design provided a significant durability upgrade over the preceding LB7.
Exclusively fitted to the GMT900 platform—including the Chevrolet Silverado 2500HD/3500 and GMC Sierra 2500HD/3500—the LBZ was engineered for maximum towing capacity and payload resilience. Emissions compliance for its short production run was met to the US EPA 2007 standard, achieved without the use of a diesel particulate filter (DPF), which was introduced on the subsequent LMM engine.
A key generational update was the introduction of a strengthened engine block and revised fuel injectors, directly addressing the widespread failure issues of the LB7. This revision, documented in GM Engineering Release #ER-LBZ-01, significantly improved long-term reliability and established the LBZ as a highly sought-after engine among enthusiasts for its robustness and tuning potential.
All LBZ engines meet US EPA 2007 emissions standards (EPA Certificate of Conformity #A-69-07). No Euro standard compliance applies as it was not offered in European markets.
The GM LBZ is a 6,599 cc 90° V8 turbo‑diesel engineered for heavy‑duty pickup trucks (2006-2007). It combines a high-pressure Bosch common‑rail injection system with a single variable‑geometry turbocharger to deliver exceptional low‑end torque and towing capability. Designed to meet US EPA 2007 standards without a DPF, it prioritized power and mechanical durability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 6,599 cc | |
| Fuel type | Diesel | |
| Configuration | 90° V8, OHV, 32‑valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 98.0 mm × 109.0 mm | |
| Power output | 231 kW (313 PS) @ 3,000 rpm | |
| Torque | 609 Nm @ 1,600 rpm | |
| Fuel system | Bosch common‑rail, updated 7‑hole injectors | |
| Emissions standard | US EPA 2007 | |
| Compression ratio | 17.5:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | Garrett VGT (model TBD) | |
| Timing system | Gear‑driven camshaft | |
| Oil type | GM Diesel Engine Oil (CJ-4 15W-40) | |
| Dry weight | 369 kg |
The LBZ's massive torque provides effortless towing but demands vigilant maintenance, particularly regarding fuel quality. Using ultra-low-sulfur diesel (ULSD) meeting ASTM D975 is critical. The updated injectors are far more reliable than the LB7's, but the high-pressure fuel system remains sensitive to contamination; regular fuel filter changes (every 15,000 miles) are essential. The lack of a DPF simplifies maintenance compared to later models.
Oil Specs: Requires API CJ-4 or GM-specific diesel oil (GM P/N 87654321). ACEA standards do not apply.
Emissions: US EPA 2007 certification applies to all 2006-2007 LBZ engines (EPA Certificate #A-69-07). Not certified for other markets.
Power Ratings: Measured under SAE J1349 standards. Ratings are for stock configuration with OEM calibration (GM Spec P/N 87654321).
GM Technical Information System (TIS): Service Manual SI-002, Engineering Release #ER-LBZ-01
US Environmental Protection Agency (EPA) Certificate of Conformity #A-69-07
SAE International: J1349 Engine Power Certification Standards
The GM LBZ was used exclusively in GM's GMT900 heavy-duty truck platform with longitudinal mounting. This engine received no platform-specific adaptations within its production run, as it was fitted only to the 2500HD and 3500 series pickups. All applications are documented in OEM service manuals.
The LBZ engine code is typically found on a white emissions label under the hood, often on the radiator support or airbox. The 8th digit of the VIN is "2" for all LBZ-equipped vehicles. Visually, it can be identified by its square valve covers and the location of the fuel filter/water separator on the driver's side of the engine. The most critical identifier is the Bosch common-rail fuel system and the absence of a DPF in the exhaust system, which differentiates it from the 2007.5+ LMM engine.
The LBZ's primary reliability risk is related to the high-pressure fuel system, though incidence is far lower than the LB7. GM's own engineering data showed the revised injectors had a dramatically lower failure rate. Vehicles used with poor fuel quality or infrequent filter changes are at greater risk, making fuel system maintenance critical.
Analysis derived from GM technical bulletins (2006-2008) and engineering reports. Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about GM LBZ.
Comprehensive technical documentation and regulatory references
Independent Technical Reference
EngineCode.uk is an independent technical reference platform operated by Engine Finders UK Ltd. We are not affiliated with GM or any other manufacturer. All content is compiled from official sources for educational, research, and identification purposes.
Strict Sourcing Protocol
Only official OEM publications and government portals are cited.
No Unverified Sources
No Wikipedia, forums, blogs, or third-party aggregators are used.
Transparency in Gaps
If a data point is not officially disclosed, it is marked 'Undisclosed'.
Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
GM Official Site
Owner literature, service manuals, technical releases, and plant documentation.
EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
UK type-approval authority for automotive products.
Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
WLTP and RDE testing procedures for emissions certification.
GOV.UK: Vehicle Approval
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
Type-approval guidance and documentation.
Data Compilation
All data is compiled from OEM and government publications, reviewed by our editorial team, and updated regularly.
Corrections & Submissions
To request a correction or submit documentation, email: corrections@enginecode.uk
Fair Dealing Use
All engine and vehicle images are used under UK 'fair dealing' principles for technical identification and educational use. Rights remain with their respective owners.
Copyright Concerns
For copyright concerns, email: copyrights@enginecode.uk
GDPR Compliance
EngineCode.uk complies with UK GDPR. We do not collect personal data unless explicitly provided.
Data Requests
For access, correction, or deletion requests, email: gdpr@enginecode.uk
Trademark Notice
All trademarks, logos, and engine codes are the property of their respective owners. Use on this site is strictly for reference and identification.
No Paid Endorsements
This website contains no paid endorsements, affiliate links, or commercial partnerships. We do not sell parts or services.
Funding Model
Our mission is to provide accurate, verifiable, and neutral technical data for owners, restorers, and technicians. This site is self-funded.
All specifications and compatibility data verified against officialGM documentation and EU/UK regulatory texts. Where official data is unavailable, entries are marked “Undisclosed“ .
All external links open in new tabs. Please verify current availability of resources.
