The 2006 STS-V packs the hand-built supercharged Northstar 4.4L V8 with serious performance potential, but it's plagued by catastrophic engine failures stemming from weak piston ring lands and inadequate oiling under boost—expect major lower-end work if you push it hard or buy one with unknown history.
Piston Ring Land Failure / Cracked Pistons
Common · high severity
Typical onset: 60,000-100,000 mi
Symptoms: Excessive oil consumption (1 qt per 500-1000 miles), White or blue smoke on startup and under load, Loss of compression in one or more cylinders, Rough idle and misfires, Metallic rattling from engine bay
Fix: The supercharged Northstar uses hypereutectic pistons with thin ring lands that crack under detonation or sustained boost. Full engine-out teardown required: replace all pistons with forged aftermarket units, new rings, bearings, gaskets, ARP head studs recommended. Budget 40-50 hours labor for complete rebuild including machine work and reassembly.
Estimated cost: $8,000-15,000
Main and Rod Bearing Wear
Occasional · high severity
Typical onset: 80,000-120,000 mi
Symptoms: Deep knocking noise from lower engine, especially cold starts, Metallic ticking that increases with RPM, Low oil pressure warning at idle when hot, Metal shavings in oil during changes
Fix: Northstar oiling system struggles under high lateral G-loads and sustained high RPM—bearings starve and wear. Requires full engine removal, crankshaft inspection/polishing or replacement, all new bearings, thrust washers. Often discovered during piston repairs. 35-45 hours labor if caught early; if crank is scored, add machining time and cost.
Estimated cost: $6,000-10,000
Head Gasket Failure (Both Banks)
Occasional · high severity
Typical onset: 70,000-110,000 mi
Symptoms: Coolant loss with no visible leaks, White exhaust smoke, Overheating under load, Milky oil or oil in coolant reservoir, Rough running after warmup
Fix: While improved over earlier Northstars, the STS-V still uses the same head bolt configuration prone to gasket weeping. Engine-out job for proper access to all 20 head bolts per side; machine heads flat, install Time-Sert inserts in stripped bolt holes if present, new gaskets and ARP studs highly recommended. 30-38 hours labor.
Estimated cost: $5,500-8,500
Transmission Oil Cooler Line Leaks
Common · medium severity
Typical onset: 50,000-90,000 mi
Symptoms: Red fluid spots under vehicle, Burnt transmission fluid smell, Transmission slipping or delayed engagement when hot, Low fluid level on dipstick check
Fix: The 6L80 transmission cooler lines corrode at connections or crack from heat cycling. Lines run along frame rails and are exposed to road salt. Replace both pressure and return lines as a set, flush cooler, refill with Dexron VI. 2-3 hours labor if caught before transmission damage occurs.
Estimated cost: $400-700
Transmission Mount Failure
Common · low severity
Typical onset: 60,000-100,000 mi
Symptoms: Clunking when shifting from Park to Drive or Reverse, Excessive vibration at idle in gear, Visible sagging of transmission tailshaft, Harsh engagement into gear
Fix: The rear transmission mount deteriorates from the torque of the supercharged V8 and heat from exhaust proximity. Direct replacement with OEM or polyurethane upgraded mount. Requires supporting transmission, removing crossmember. 1.5-2 hours labor.
Estimated cost: $250-450
Fuel Filter Clogging / Fuel Pump Failure
Occasional · medium severity
Typical onset: 80,000-120,000 mi
Symptoms: Hard starting when hot, Loss of power under heavy throttle, Stuttering or hesitation during acceleration, Engine stalling at idle after spirited driving, Fuel pump whine from rear of vehicle
Fix: In-tank fuel pump and filter assembly struggles with ethanol fuel degradation and sediment buildup. The high-pressure fuel system for the supercharged engine is sensitive to flow restrictions. Drop fuel tank, replace entire pump/filter/level sender assembly. 3-4 hours labor.
Estimated cost: $800-1,200
Owner tips
Change oil every 3,000-4,000 miles with quality synthetic—the supercharged Northstar is unforgiving with extended intervals
Avoid sustained high-RPM pulls until engine is fully heat-soaked; cold detonation kills pistons
Install aftermarket oil catch can to reduce carbon buildup from PCV system
Budget $10K-15K engine rebuild fund if buying over 70K miles—it's not 'if' but 'when' with hard-driven examples
Use 91+ octane religiously; lower grades cause detonation that destroys ring lands
Check for engine rebuild history and receipts—a properly rebuilt LC3 with forged internals is actually MORE desirable than original
Only buy if you're prepared for a $10K+ engine rebuild or find one already done right with forged pistons—this is a $15K car with a $12K ticking time bomb under the hood.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.
Fitment notes: Battery located in trunk; high-performance AGM battery required for supercharged engine demands
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Every control module on the 2006-2009 Cadillac STS-V — where it lives, replacement time, and what it takes to program a replacement. Modules marked dealer / factory tool won't work after a part swap alone — budget for programming.
📍 Trunk area, driver side, mounted to body structure near tail lamp
🔧 Tech 2 or Autel
⚠️ Sensor calibration may be required; rear parking sensors only on STS-V
Seat Control Module (SCM)0.6 hr R&Rrelearn only +0.1 hr▸ programming details
📍 Under driver and passenger seats, mounted to seat frame
🔧 Tech 2
⚠️ Memory seat position relearn required; heated/cooled seat functions
Aftermarket tool coverage varies by software version and vehicle build — treat "aftermarket tool" rows as "usually possible" and verify against your tool maker's coverage list before promising a customer. Spot a wrong location or hour? Tell us — corrections ship fast here.
General Motors LLC (GM) is recalling certain model year 2004-2007 Cadillac CTS-V vehicles manufactured October 6, 2003, to March 15, 2007, and 2006-2007 Cadillac STS-V vehicles manufactured June 23, 2005, to March 15, 2007. In the affected vehicles, the electrical terminals of the fuel pump module may overheat resulting in the melting of the flange material.
Consequence: If the flange melts, a hole may be created allowing the fuel pump to leak fuel, causing the vehicle to stall, increasing the risk of a vehicle crash. Additionally, leaking fuel in the presence of an ignition source increases the risk of a fire.
Remedy: GM will notify owners, and dealers will replace the fuel module and fuel tank jumper harness, free of charge. GM sent out interim notices in late October. The recall began on March 12, 2015. Owners may contact Cadillac customer service at 1-800-458-8006. GM's number for this recall is 14405.
POWER TRAIN:AXLE ASSEMBLY:AXLE SHAFT:SEAL · 07V589000
2007-12-20 · PE07037
ON CERTAIN PASSENGER VEHICLES, THE REAR AXLE PINION SEAL DOES NOT MEET ALL OF THE SPECIFICATIONS AND MAY EXPERIENCE A FLUID LEAK.
Consequence: A REAR DIFFERENTIAL FAILURE MAY CAUSE LOSS OF MOTIVE POWER AND POSSIBLY LOSS OF CONTROL INCREASING THE RISK OF A CRASH.
Remedy: DEALERS WILL REPLACE THE PINION SEAL FREE OF CHARGE. THE RECALL BEGAN ON FEBRUARY 1, 2008. OWNERS MAY CONTACT CADILLAC AT 1-800-458-8006 OR HTTP://WWW.CADILLAC.COM; PONTIAC AT 1-800-620-7668 OR HTTP://WWW.PONTIAC.COM; AND SATURN AT 1-800-972-8876 OR HTTP://WWW.SATURN.COM.
FUEL SYSTEM, GASOLINE:DELIVERY · 06V020000
2006-01-25
CERTAIN VEHICLES EQUIPPED WITH V6 ENGINES MAY HAVE A CONDITION WHERE FUEL IS NO LONGER SUPPLIED TO THE ENGINE. THIS CONDITION OCCURS WITHOUT THE ILLUMINATION OF THE FUEL LEVEL LOW INDICATOR LIGHT OR THE WARNING CHIME.
Consequence: IF THE ENGINE STOPS RUNNING, THE OPERATOR WILL NOT BE ABLE TO RESTART THE VEHICLE WHICH COULD INCREASE THE RISK OF A CRASH.
Remedy: DEALERS WILL REPROGRAM THE ELECTRONIC CONTROL MODULE (ECM) WITH NEW SOFTWARE FREE OF CHARGE. OWNERS WERE NOTIFIED IN DECEMBER 2005 AND ASKED TO MAINTAIN AT LEAST 1/4 OF A TANK FUEL LEVEL TO AVOID THIS CONDITION UNTIL THE PARTS ARE AVAILABLE. THE PARTS ARE NOW AVAILABLE, OWNER RENOTIFICATION BEGAN ON MARCH 23, 2006. OWNERS MAY CONTACT CADILLAC AT 1-866-982-2339.
VEHICLE SPEED CONTROL · 06V007000
2006-01-13
ON CERTAIN PASSENGER VEHICLES EQUIPPED WITH ALL WHEEL DRIVE AND A 3.6L V6 ENGINE, THE TORQUE MONITORING FUNCTIONS OF THE ELECTRONIC THROTTLE CONTROL (ETC) ARE NOT ENABLED. THESE FUNCTIONS CAN LIMIT ENGINE SPEED AND TORQUE IF UNUSUAL ENGINE CONTROL MODULE (ECM) HARDWARE OR SOFTWARE FAILURES OCCUR.
Consequence: WITHOUT THESE FUNCTIONS ENABLED, A PERSISTENT ECM FAILURE COULD RESULT IN A THROTTLE OPENING GREATER THAN COMMANDED BY THE DRIVER AND A CRASH COULD OCCUR.
Remedy: DEALERS WILL REPROGRAM THE ECM ON THESE VEHICLES FREE OF CHARGE. THE RECALL BEGAN ON JANUARY 24, 2006. OWNERS MAY CONTACT CADILLAC AT 1-866-982-2339.
Performance
Horsepower
469hp
Torque
439lb-ft
0–60 mph
4.6sec
Quarter mile
13.0sec
Top speed
175mph
Fuel economy (EPA)
City
12mpg
Highway
19mpg
Combined
14mpg
Fuel
Premium Gasoline
Capability & size
Curb weight
4,270lb
EPA class
Midsize Cars
Wiper blades
Performance variant shares same wiper specifications as base STS. Sedan body style, no rear wiper.
Size-standard part numbers — verify your connector type before buying. Rear blades are model-specific; check the package's vehicle list.
Fuel economy figures are EPA data via fueleconomy.gov (median across matching trims). Performance figures are compiled estimates for the 2006 Cadillac STS-V 4.4L Supercharged V8 and can vary by trim.
🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Lexus & Toyota Mechanic · 20+ years.