The Chevrolet LQ4 is a 6,000 cc, V8 gasoline engine produced between 2002 and 2009. It features overhead valve (OHV) architecture with two valves per cylinder, sequential multi-port fuel injection, and a cast-iron block with aluminum heads. In standard configuration, it delivers 300 hp (224 kW) and 360 lb-ft (488 Nm) of torque, providing strong low-end pulling power ideal for towing and heavy-duty applications.
Fitted to models such as the Chevrolet Silverado 1500, Chevrolet Suburban, and Chevrolet Tahoe, the LQ4 was engineered for durability in full-size trucks and SUVs. It meets emissions standards through exhaust gas recirculation (EGR), catalytic converters, and closed-loop fuel control, allowing compliance with EPA Tier 2 Bin 5 and California LEV II ULEV-200 standards across its production run.
One documented concern is intake manifold gasket leakage observed in 2003–2005 production units, highlighted in General Motors Service Information Bulletin 05167. The issue arises from degradation of the molded rubber gasket due to prolonged thermal cycling, leading to vacuum leaks and rough idle. GM issued an updated multi-layer steel (MLS) gasket in 2006 to resolve the condition.
Production years 2002–2005 meet EPA Tier 2 Bin 5; 2006–2009 models comply with updated evaporative emissions requirements (EPA-HQ-OAR-2009-0695).
The Chevrolet LQ4 is a 6,000 cc V8 gasoline engine engineered for full-size truck and SUV platforms (2002–2009). It combines OHV pushrod design with sequential fuel injection to deliver robust low-end torque and long-term durability. Designed to meet EPA Tier 2 Bin 5 and California LEV II standards, it balances heavy-duty performance with emissions compliance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 6,000 cc | |
| Fuel type | Gasoline | |
| Configuration | V8, OHV, 16-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 101.6 mm × 92.0 mm | |
| Power output | 224 kW (300 PS) @ 4,400 rpm | |
| Torque | 488 Nm @ 4,000 rpm | |
| Fuel system | Sequential multi-port fuel injection | |
| Emissions standard | EPA Tier 2 Bin 5, LEV II ULEV-200 | |
| Compression ratio | 9.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Double roller chain | |
| Oil type | GM 4718M 10W-30 or 5W-30 | |
| Dry weight | 215 kg |
The LQ4's OHV design provides strong low-RPM torque ideal for towing and hauling, but requires adherence to 10,000-mile oil change intervals to prevent lifter wear and timing chain degradation. GM 4718M 10W-30 or 5W-30 oil is recommended due to its shear stability and compatibility with the hydraulic lifter system. The sequential fuel injection demands TOP TIER detergent gasoline to prevent injector clogging. Post-2006 models feature updated MLS intake manifold gaskets; pre-2006 units should be inspected per GM SIB 05167. Catalytic converters require monitoring to avoid thermal degradation from prolonged rich mixtures or misfires.
Oil Specs: Requires GM 4718M specification (GM SIB 05167). Supersedes earlier GM oil standards.
Emissions: EPA Tier 2 Bin 5 applies to all 2002–2009 models (EPA File EPA-2002-CHEV-003). California models meet LEV II ULEV-200 standards.
Power Ratings: Measured under SAE J1349. Output assumes 87 octane fuel (GM TIS Doc. 30781).
General Motors Technical Information System (TIS): Docs 30781, 31003, SIB 05167
EPA Certification Database (EPA-2002-CHEV-003)
SAE International: J1349 Engine Power Certification Standards
The Chevrolet LQ4 was used across Chevrolet's GMT800/GMT900 platforms with longitudinal mounting and shared architecture with GMC and Holden variants. This engine received platform-specific adaptations-reinforced cylinder heads in the Suburban and revised intake tuning in the Tahoe-and from 2006 the facelifted Silverado models adopted the LQ4 with updated intake gaskets and ECU calibration, creating interchange limits. Partnerships allowed Holden's Caprice to use the LQ4 with minor calibration differences. All adaptations are documented in OEM technical bulletins.
Locate the engine ID tag on the passenger side cylinder head near the exhaust manifold (GM TIS 30781). The 8th VIN digit indicates engine type ('L' for LQ4 series). Pre-2006 models have silver valve covers with black coil packs; post-2006 units use black valve covers with chrome accents. Critical differentiation from LQ9: LQ4 has a 9.5:1 compression ratio and cast-iron block, while LQ9 is a high-output version with 10.1:1 compression. Service parts require model year verification - intake manifold gaskets for 2002–2005 models are incompatible with 2006+ due to material redesign (GM SIB 05167).
The LQ4's primary reliability risk is intake manifold gasket leakage in early production models, with elevated incidence in high-temperature and stop-start applications. Internal GM quality reports from 2006 indicated approximately 7% of 2003–2005 units required gasket replacement before 120,000 miles, while NHTSA field reports confirm related rough idle and SES light entries. Frequent thermal cycling and urban driving accelerate gasket fatigue, making timely inspection and preventive replacement critical.
Analysis derived from General Motors technical bulletins (2002-2009) and NHTSA failure statistics (2003-2012). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about CHEVROLET LQ4-61CUL4.
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 CHEVROLET 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.
CHEVROLET 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 officialCHEVROLET 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.
