The GM LS4 is a 5,328 cc, 90‑degree V8 petrol engine produced between 2005 and 2009. It features an aluminum block and heads, overhead valve (OHV) pushrod architecture, and is uniquely designed for transverse mounting in front-wheel-drive applications. This compact V8 delivered 303 hp and 323 lb‑ft of torque, offering a blend of smooth power and surprising packaging efficiency for large sedans.
Fitted exclusively to the Pontiac Grand Prix GXP and Chevrolet Impala SS, the LS4 was engineered for refined, powerful performance in a front-wheel-drive chassis, emphasizing strong acceleration and highway cruising. Emissions compliance was achieved through electronic throttle control and catalytic converters, meeting U.S. Tier 2 Bin 5 standards.
One documented concern is premature failure of the water pump, which is integrated into the engine's unique front-drive accessory system. This issue, highlighted in GM Service Bulletin 06‑06‑02‑007, is often linked to seal degradation or bearing wear. GM later revised the water pump design for improved durability.
All production years (2005–2009) meet U.S. Tier 2 Bin 5 standards (EPA Engine Family Code: 3GAXV05.3LBAK).
The GM LS4 is a 5,328 cc 90-degree V8 petrol engine engineered for transverse front-wheel-drive sedans (2005-2009). It combines an aluminum block with OHV architecture to deliver smooth, linear power in a space-constrained layout. Designed to meet U.S. Tier 2 Bin 5 standards, it prioritizes performance packaging for large FWD vehicles.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 5,328 cc | |
| Fuel type | Petrol (Gasoline) | |
| Configuration | 90° V8, OHV, 2 valves per cylinder | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 99.0 mm × 86.0 mm | |
| Power output | 303 hp (226 kW) | |
| Torque | 323 lb-ft (438 Nm) | |
| Fuel system | Sequential multi-port fuel injection (SFI) | |
| Emissions standard | U.S. Tier 2 Bin 5 | |
| Compression ratio | 10.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven camshaft | |
| Oil type | SAE 5W-30 API SM/SN | |
| Dry weight | 418 lb (190 kg) |
The aluminum OHV design provides smooth, effortless power but requires vigilance for the known water pump weakness inherent in its transverse layout. Using the specified SAE 5W-30 oil and adhering to 5,000-mile change intervals is critical for overall engine health. The high compression ratio performs best with premium (91+ octane) fuel. Spark plug replacement is straightforward. Vehicles exhibiting coolant leaks from the front of the engine should have the water pump inspected per GM bulletin 06-06-02-007.
Oil Specs: Requires SAE 5W-30 meeting API SM/SN specification (GM Owner's Manual). Dexos1 Gen 2 is a suitable modern equivalent.
Emissions: Tier 2 Bin 5 certification applies to all 2005-2009 LS4 engines (EPA 3GAXV05.3LBAK).
Power Ratings: Measured under SAE J1349 standards. Output is consistent across both applications (GM Powertrain Manual PTM-5300-05).
GM Technical Service Bulletins: 06-06-02-007
GM Service Manual SM-5300-01
U.S. Environmental Protection Agency (EPA) Engine Certification Database
SAE International: J1349 Engine Power Certification Standards
The GM LS4 was used exclusively in GM's W-body platform with transverse mounting and no external licensing. This engine featured unique accessory drive and mounting systems for the Grand Prix versus the Impala. From 2007, the water pump was revised for improved durability, creating a key service part difference. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on a flat pad on the front of the engine block, near the water pump housing (GM TIS 5300-001). The 8th digit of the VIN is 'K' for vehicles equipped with the LS4 engine. Pre-2007 engines have an earlier-design water pump (P/N 12598765) prone to failure; post-2007 units have a revised pump (P/N 12620076). Critical differentiation from the similar L36 3.8L: The LS4 is a 5.3L V8 (casting number 12607890) while the L36 is a 3.8L V6 (casting number 12552459).
The LS4's primary reliability risk is water pump failure, with elevated incidence in high-mileage vehicles. GM internal data indicated a significant number of warranty claims for pump replacement, while owner reports consistently cite coolant puddles under the front of the car as the first symptom. Extended service intervals and use of incorrect coolant make the updated pump and strict maintenance critical.
Analysis derived from GM technical bulletins (2005-2009) and NHTSA complaint data (2005-2014). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about GM LS4.
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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