The Chevrolet LY9 is a 5,967 cc, V8 gasoline engine produced between 2007 and 2011. It features overhead valve (OHV) architecture with two valves per cylinder, sequential multi — port fuel injection, and an aluminum block and heads. In standard configuration, it delivers 315 hp (235 kW) and 338 lb — ft (458 Nm) of torque, providing strong low — end pulling power ideal for full — size trucks and SUVs.
Fitted to models such as the Chevrolet Tahoe, Chevrolet Suburban, and GMC Yukon…
Chevrolet
Production years 2007–2009 meet EPA Tier 2 Bin 5; 2010–2011 models comply with updated evaporative emissions requirements (EPA-HQ-OAR-2009-0695).
The Chevrolet LY9 is a 5,967 cc V8 gasoline engine engineered for full-size truck and SUV platforms (2007–2011). 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 | 5,967 cc | |
Fuel type | Gasoline | |
Configuration | V8, OHV, 16-valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 101.6 mm × 92.0 mm | |
Power output | 235 kW (315 PS) @ 5,400 rpm | |
Torque | 458 Nm @ 4,400 rpm | |
Fuel system | Sequential multi-port fuel injection | |
Emissions standard | EPA Tier 2 Bin 5, LEV II ULEV-200 | |
Compression ratio | 9.9:1 | |
Cooling system | Water-cooled | |
Turbocharger | Not applicable | |
Timing system | Double roller chain | |
Oil type | GM 4718M 10W-30 or 5W-30 | |
Dry weight | 210 kg |
The Chevrolet LY9 was used across Chevrolet's GMT900 platform with longitudinal mounting and shared architecture with GMC variants. This engine received platform-specific adaptations-reinforced cylinder heads in the Suburban and revised intake tuning in the Tahoe-and from 2010 the facelifted Tahoe models adopted the LY9 with updated intake gaskets and ECU calibration, creating interchange limits. Partnerships allowed GMC's Yukon to use the LY9 with minor calibration differences. All adaptations are documented in OEM technical bulletins.
The LY9'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 2010 indicated approximately 6% of 2008–2009 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 (2007-2011) and NHTSA failure statistics (2008-2015). Repair procedures should follow manufacturer guidelines.
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The LY9 is generally robust when maintained properly, but 2008–2009 models had intake gasket issues. Later revisions with MLS gaskets resolved the problem. Regular oil changes with GM 4718M oil and timely replacement of known wear items (gaskets, water pump) ensure long-term reliability. Well-maintained engines often exceed 250,000 miles without major repairs.
The most documented issues are intake manifold gasket leaks (especially in 2008–2009), camshaft lifter wear, coolant leaks from intake manifold, and valve cover oil seepage. These are addressed in GM service bulletins and are manageable with preventive maintenance and proper service intervals.
The LY9 was used in the Chevrolet Tahoe (2007–2011), Suburban (2007–2011), and GMC Yukon (2007–2011). It was a standard-output version of the Vortec 6000 family, designed for full-size SUVs. It was succeeded by the LMG in later Tahoe models.
Yes. The LY9 responds well to ECU tuning, typically gaining 20–30 hp with a performance tune. Cold air intakes, exhaust upgrades, and throttle body spacers provide additional gains. Stock internals are durable, but aggressive tuning should include upgraded cooling and fuel delivery for reliability.
EPA ratings range from 14 mpg city to 20 mpg highway (16.8–11.8 L/100km). Real-world consumption is typically 16–18 mpg (14.7–13.1 L/100km) on mixed driving. The Tahoe achieves slightly better economy than the heavier Suburban. Driving style significantly impacts actual fuel use.
Yes. The LY9 is an interference engine, meaning piston-to-valve contact will occur if the timing chain fails or jumps. This can result in bent valves and severe internal damage. Maintaining the timing chain and tensioners per schedule is essential to prevent costly repairs.
GM specifies 10W-30 or 5W-30 oil meeting GM 4718M specification for the LY9. Oil changes should be performed every 7,500 miles or 12 months, whichever comes first. Using non-spec oil may void powertrain coverage and increase risk of lifter wear in susceptible model years.
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