The Cadillac STS typically uses a 4.6-liter Northstar V8 engine, a refined aluminum V8 that powers most standard models. In the performance-focused STS-V variant, a supercharged 4.4-liter Northstar V8 delivers significantly more power.
Launched in the mid-2000s and designed as a comfortable, high-end sedan, the STS sits on Cadillac’s Northstar-based engineering lineage. The standard engine and its high-performance sibling reflect Cadillac’s pursuit of smooth power, quiet operation, and refined highway manners. This article explains the motor’s core characteristics and how they differ between the mainstream STS and the STS-V.
Engine basics
Standard STS engine
Most Cadillac STS models from the mid-2000s to the early 2010s are equipped with the Northstar 4.6-liter V8. This is an aluminum-block, dual overhead cam (DOHC) V8 with 32 valves, designed for a balance of power and refinement in a luxury sedan.
Key specifications and features of the standard engine include:
- Displacement: 4.6 liters
- Engine family: Northstar V8
- Valvetrain: DOHC, 32 valves
- Fuel system: Sequential multi-point fuel injection
- Estimated output: Approximately 320 horsepower and about 300–322 lb-ft of torque, depending on year and emissions calibration
- Design notes: Aluminum construction for reduced weight and a focus on smooth, quiet operation
In practice, the Northstar 4.6L V8 powered the STS with a focus on upscale performance and refinement, pairing well with the car’s long-wheelbase comfort and insulating cabin.
Variants and options
STS-V variant
A high-performance version known as the STS-V exists as a rarer, higher-performance model. The STS-V uses a supercharged Northstar-based V8, sized around 4.4 liters, tuned to deliver substantially more horsepower and torque than the standard STS engine. This variant was produced for a limited period and is recognized for its acceleration credentials and advanced hardware compared to the base STS.
Highlights of the STS-V’s powertrain include:
- Displacement: Approximately 4.4 liters (Northstar family)
- Forced induction: Supercharged V8
- Output: Significantly higher horsepower and torque than the standard STS engine
- Character: Tuned for brisk acceleration while maintaining Cadillac’s luxury-sedan emphasis
For most buyers and typical used-market inquiries, the standard 4.6-liter Northstar V8 is the engine most commonly associated with the Cadillac STS, with the STS-V representing the extreme end of the model’s performance spectrum.
Summary
In short, the Cadillac STS is powered by a Northstar V8. The standard model uses a 4.6-liter aluminum DOHC V8, delivering smooth and ample power for a luxury sedan. A high-performance STS-V variant exists that employs a supercharged 4.4-liter Northstar V8 for markedly higher output. Together, these engines reflect Cadillac’s emphasis on refined powertrains in the STS lineup.