The GM LJ9 is a 3,496 cc, 60‑degree V6 petrol engine produced between 2004 and 2006. It features a single overhead camshaft (SOHC), variable valve timing (VVT), and sequential fuel injection. In standard form it delivered 147 kW (197 PS), with peak torque of 305 Nm, providing smooth, adequate power for mid-size SUV applications.
Fitted to models such as the Chevrolet Colorado, GMC Canyon, and Isuzu i‑280, the LJ9 was engineered for durability and low-end torque in truck-based platforms. Emissions compliance was achieved through precise fuel metering and three-way catalytic converters, meeting stringent Tier 2 standards across its production run.
One documented concern is premature failure of the camshaft position actuators, which can trigger check engine lights and affect performance. This issue, highlighted in GM Service Bulletin 05‑06‑01‑003A, is often linked to oil flow restrictions or solenoid wear. Revised actuators were introduced for the 2006 model year to address the concern.
Production years 2004–2006 meet EPA Tier 2 standards (EPA Engine Family Code: GMVLJ9.04T2).
The GM LJ9 is a 3,496 cc 60-degree V6 petrol engine engineered for mid-size trucks and SUVs (2004-2006). It combines SOHC with variable valve timing to deliver smooth, low-end torque and responsive power for towing and load-carrying. Designed to meet EPA Tier 2 standards, it balances performance with regulatory compliance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 3,496 cc | |
| Fuel type | Petrol | |
| Configuration | 60° V6, SOHC, 12-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 99.0 mm × 76.0 mm | |
| Power output | 147 kW (197 PS) @ 5,600 rpm | |
| Torque | 305 Nm @ 2,800 rpm | |
| Fuel system | Sequential multi-port fuel injection | |
| Emissions standard | EPA Tier 2 | |
| Compression ratio | 9.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven | |
| Oil type | API SM (SAE 5W-30) | |
| Dry weight | 170 kg |
The SOHC VVT system provides strong low-end torque ideal for truck applications but requires strict adherence to 7,500 km oil change intervals to prevent cam actuator failure and timing chain wear. API SM specification is critical due to its specific anti-wear properties protecting the VVT solenoids. The engine is sensitive to low oil levels; regular checks are advised. Revised camshaft position actuators are available per GM SIB 05-06-01-003A for pre-2006 models. The ECU is calibrated for 87 RON fuel; higher octane provides no benefit.
Oil Specs: Requires API SM (5W-30) specification (GM SIB 05-06-01-003A).
Emissions: EPA Tier 2 certification applies to all 2004–2006 models (EPA Engine Family Code: GMVLJ9.04T2).
Power Ratings: Measured under SAE J1349 standards. Rated for 87 RON fuel (GM Service Manual SI-C0400).
GM Technical Service Information: Docs SI-C0400, 05-06-01-003A
EPA Engine Family Database (GMVLJ9.04T2)
SAE International: J1349 Engine Power Certification Standards
The GM LJ9 was used across GM's GMT355 platform with longitudinal mounting. This engine received platform-specific adaptations-unique engine mounts for the Isuzu i-280 and specific intake manifolds for the Chevrolet Colorado-creating minor interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front of the engine block, near the timing cover (GM Service Manual SI-C0400). The 8th VIN digit for LJ9-equipped vehicles is typically '9'. Pre-2006 models use an earlier design camshaft actuator (black solenoid body); 2006 units have a revised actuator (grey solenoid body). Critical differentiation from the LL8 3.5L: LJ9 has a unique intake manifold casting number and SOHC valve covers. Service parts, particularly for the VVT system, require production date verification - actuators for engines before 01/2006 are incompatible with later units due to solenoid redesign (GM SIB 05-06-01-003A).
The LJ9's primary reliability risk is camshaft position actuator failure, with elevated incidence in vehicles with extended oil change intervals. GM internal data indicated a notable failure rate before 80,000 km in pre-2006 builds, while general repair data shows these actuators as a common replacement item. Neglected oil changes make actuator replacement critical.
Analysis derived from GM technical bulletins (2004-2006) and NHTSA complaint data (2005-2010). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about GM LJ9.
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