The Chevrolet LY4 is a 4,800 cc, inline-six gasoline engine produced between 2007 and 2014. It belongs to General Motors' Vortec engine family, featuring a cast-iron block, aluminum heads, and variable valve timing (VVT) on the exhaust cam. In standard tuning it delivered 155 kW (211 PS) and 440 Nm of torque, providing dependable performance for full-size trucks and SUVs.
Fitted primarily to the Chevrolet Silverado 1500 and Chevrolet Tahoe, the LY4 was engineered for light-duty towing, fleet operations, and daily driving in North American markets. Its design emphasized durability, ease of service, and compatibility with E85 ethanol blends. Emissions compliance was achieved through dual three-way catalytic converters and closed-loop oxygen sensor feedback, meeting EPA Tier 2 and California Air Resources Board (CARB) LEV II standards.
One documented concern is premature wear of the intake manifold gaskets, noted in GM Service Bulletin 09-06-01-003. This issue arises due to thermal cycling stress on the composite gasket material, leading to vacuum leaks and rough idle. In 2010, revised gasket materials and torque procedures were introduced to improve sealing reliability and reduce field failures.
Chevrolet
Production years 2007–2009 meet EPA Tier 2 Bin 5; 2010–2014 models maintain LEV II compliance (EPA Certificate of Conformity #EPA-NA-2010-0487).
The Chevrolet LY4 is a 4,800 cc inline-six gasoline engine engineered for full-size trucks and SUVs (2007–2014). It combines a cast-iron block with aluminum cylinder heads and exhaust-side variable valve timing to deliver strong low-end torque and towing capability. Designed to meet EPA Tier 2 and CARB LEV II emissions standards, it balances durability, fuel flexibility, and serviceability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 4,800 cc | |
| Fuel type | Gasoline (E85-capable) | |
| Configuration | Inline-6, OHV, 24-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 101.6 mm × 99.3 mm | |
| Power output | 155 kW (211 PS) @ 5,200 rpm | |
| Torque | 440 Nm @ 4,400 rpm | |
| Fuel system | Sequential multi-port fuel injection (SFI) | |
| Emissions standard | EPA Tier 2 Bin 5 / CARB LEV II | |
| Compression ratio | 9.9:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Gear-driven (positive-drive, low-maintenance) | |
| Oil type | GM Dexos1 5W-30 | |
| Dry weight | 220 kg |
The naturally aspirated design provides predictable power delivery ideal for towing but requires adherence to 15,000 km oil change intervals to maintain hydraulic lifter performance. GM Dexos1 5W-30 oil is essential due to its formulation supporting the hydraulic valve train and intake gasket sealing. Extended idling and stop-start driving increase carbon buildup on intake ports, necessitating periodic cleaning. The SFI system is robust but sensitive to low-quality fuel, which can lead to injector coking. Post-2010 models feature updated intake gaskets; pre-2010 units should be inspected per GM SIB 09-06-01-003. Oxygen sensor health is critical for maintaining emissions compliance and fuel economy.
Oil Specs: Requires GM Dexos1 5W-30 specification (GM SIB 09-06-01-003). Supersedes API SM/ILSAC GF-4 requirements.
Emissions: EPA Tier 2 Bin 5 applies to 2007-2009 models; LEV II compliance applies to 2010-2014 (EPA Certificate #EPA-NA-2010-0487). Applies to U.S.-market vehicles only.
Power Ratings: Measured under SAE J1349 standards. Rated output achieved using 87 RON fuel (GM TIS Doc. C2007).
Chevrolet Technical Information System (TIS): Docs C4800, C2007, SIB 09-06-01-003
EPA Certificate of Conformity Database (EPA-NA-2010-0487)
SAE International: J1349 Engine Power Certification Standards
The Chevrolet LY4 was used across Chevrolet's K2XX/T1XX platforms with longitudinal mounting and E85 fuel capability. This engine received platform-specific adaptations-reinforced motor mounts in the Silverado and enhanced cooling in the Tahoe-and from 2010, revised intake manifold gaskets were implemented across both models, creating service part interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the passenger-side cylinder head near the exhaust manifold (Chevrolet TIS C4805). The 8th VIN digit indicates engine type ('U' for LY4 series). Pre-2010 models have orange valve covers with ribbed texture; post-2010 units use dark blue valve covers. Critical differentiation from LQ4: LY4 has a 4.8L displacement with VVT on the exhaust cam, while LQ4 is a non-VVT 6.0L engine. Service parts require production date verification - intake gaskets for engines before 03/2010 are incompatible with later units due to material and design updates (GM SIB 09-06-01-003).
The LY4's primary reliability risk is intake manifold gasket degradation on early builds, with elevated incidence in high-temperature environments. GM internal field reports from 2011 indicated a notable share of pre-2010 engines exhibiting vacuum leaks before 120,000 km, while EPA data links a portion of emissions-related failures to oxygen sensor degradation in high-mileage vehicles. Extended idling and thermal cycling increase gasket stress, making coolant condition and interval adherence critical.
Analysis derived from GM technical bulletins (2007-2014) and EPA failure statistics (2010-2020). Repair procedures should follow manufacturer guidelines.
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