CADILLAC STS 4.6L ENGINE

Classic CADILLAC STS 4.6L ENGINE meets modern performance: the legendary CADILLAC STS 4.6L ENGINE, as found in 2005–2011 Cadillac STS sedans, combines smooth luxury with V8 power. Featuring an all‑aluminum block and heads, dual overhead cams with variable valve timing (VVT), and a 32‑valve layout, this engine produces ≈ 320 hp at 6,400 rpm and 315 lb‑ft torque at 4,400 rpm

Offered here is a complete long block assembly (crankcase, heads, camshafts, mains/brg caps, and rotating assembly), ready for bolt‑in installation with proper accessories.

 Technical Highlights

• Architecture: 90° V8, 4,565 cc displacement (93 mm bore × 84 mm stroke), aluminum block and heads, lightweight at ~436–450 lb (~200 kg)

• Power Output: 320 hp @ 6,400 rpm, 315 lb‑ft torque @ 4,400 rpm. Premium unleaded fuel required

• Features:

  • Dual Overhead Camshafts (DOHC) per bank

  • 32‑valve architecture with VVT

  • Sequential fuel injection, coil‑on‑plug ignition

  • OBD-II compliant emissions, high‑flow air intake, acoustic covers and hydraulic mounts for NVH reduction

• Cooling & Lubrication: High‑capacity liquid cooling, dual electric fans, oil cooler, wet sump with synthetic oil recommended (e.g. 5W‑30)

• Service Interval: Oil changes every 7,500 miles or 12 months; spark plugs at around 100,000 miles; coolant flush and timing belt inspection annually

 Known Weak Points & Maintenance History CADILLAC STS 4.6L ENGINE

Head Gasket Concerns

Early Northstar head bolts were torque‑to‑yield style and susceptible to stretching, which often led to head gasket failures. Symptoms included coolant loss, overheating, white exhaust smoke, and compression loss

Remanufactured rebuilds should include upgraded head bolts and precision torque settings to avoid recurrence.

Oil & Valve Cover Leaks CADILLAC STS 4.6L ENGINE

Valve cover gaskets are a notorious leak point on Northstar engines. Over time, degradation leads to oil seepage atop the heads or into accessory drive areas. Proactive gasket replacement is recommended

Cooling System Components CADILLAC STS 4.6L ENGINE

Water pump failures, thermostat malfunctions, and coolant hose degradation are common repair items. Reddit reports cite recurring thermostat failures leading to inconsistent engine temperature, overheating messages, and persistent electric fan operation even when engine is cool

Camshaft and Bucket Wear

Owners rebuilding high‑mile CADILLAC STS 4.6L ENGINE Northstars report uneven cam lobe wear and lifter bucket scoring. While some reuse cams with replacement buckets, others opt for regrinding or aftermarket replacements for longevity

Electrical/Starter Issues

The starter motor resides in the V‑bank’s valley under the intake. Replacing it requires manifold removal. Also, rodents can chew wiring in the valley, especially around knock sensor wiring, leading to intermittent engine faults or diagnostics errors

General Reliability Notes

The Northstar is smooth and powerful—but sensitive: high oil consumption, transmission jerkiness caused by worn mounts, and traction-control wheel bearing replacements (especially AWD) are recurring themes among owners, especially on AWD models. Reddit feedback suggests transmission fluid refresh, motor mount inspection or replacement, and bearing upgrades as advisable

 Why Buy This Engine?

Proven Performance CADILLAC STS 4.6L ENGINE

With nearly 320 hp and a characteristically smooth V8 glide, the Northstar engine offers luxury car refinement with genuine muscle. For Cadillac restorations or engine swaps in similar GM platforms, it remains a desirable powerplant.

OEM Fitment & Easy Bolt‑In CADILLAC STS 4.6L ENGINE

This unit is an OEM LH2-era Northstar V8, compatible with 2005–2011 STS, Seville, XLR, SRX, DTS, and some Buick/Pontiac derivatives.

Strong Aftermarket Support

Though parts are aging, remanufacturers like Fraser Engines and Tom’s Foreign Car Parts offer long-block replacements. Stand‑alone upgrades—like upgraded head bolts, billet cams, gasket kits, valve covers, and water pumps—are widely available

Ideal for Rebuild or Replacement CADILLAC STS 4.6L ENGINE

Lightly used or properly remanufactured long blocks offer a solid foundation: upgrade gaskets, belts, sensors, mounts, and intake for modern reliability.

 Buyer’s Checklist CADILLAC STS 4.6L ENGINE

 Real‑World Insights from Owners

Some CADILLAC STS 4.6L ENGINE users have offered candid observations:

 Price & Value Proposition

• Used OEM long‑block units usually range from $800 to $1,700 USD, depending on mileage and warranty — for example, eBay listings show items around $1,300 with shipping included

• Remanufactured units with upgraded head bolts and fresh gaskets may run $2,000 to $3,600, but come with warranty coverage

Factor in shipping weight (~200 kg), customs, and local duties if imported.

Conclusion

The CADILLAC STS 4.6L ENGINE remains an iconic powerplant—luxurious, potent, and full of potential for restoration or engine replacement projects. While it demands attentive maintenance—especially around head gaskets, coolant system, and electrical parts—a remanufactured or well‑examined used long‑block can deliver years of smooth, silent V8 performance. With care, and improved modern seals and hardware, this engine offers high performance and Cadillac refinement unmatched in its era.

If you’re planning a rebuild or replacement and need torque specs, breakout of included parts, or shipping quotes to your location, just let me know—I can provide a tailored quote or component list.