This vehicle has pumped through 5-7 quarts of oil appx every 500 miles. I know that this is not normal. Car was overhauled, the trans was basically rebuilt, with new components.problem with oil evaporating at very low mileage still an issue. ***no leaks*** or symptoms aside of diminishing oil every said set of miles. Very frustrating issue that hasn't been resolved. *tr
2005 Cadillac STS engine problems
severe 12 complaints filed with NHTSA · avg repair $3,100 · see engine across all vehicles →
Failure mileage
Complaints
12
Recalls
0
Avg fix
$3,100
1crash
When does it fail?
Of the 12 engine complaints filed for the 2005 Cadillac STS, here's the actual mileage breakdown — failures cluster heaviest at 50,000-75,000 mi.
0-25k
25-50k
50-75k
75-100k
100-125k
125-150k
150k+
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
What stands out
No new NHTSA engine complaint has been filed on this vehicle in over 11 years — the issue may be aging out of the active population.
The failure pattern owners describe
Buyer takeaway: The 2005 Cadillac STS shows serious engine reliability issues across multiple failure modes: uncontrolled shutdowns with safety hazards, timing chain failure, severe oil consumption, and exhaust/intake manifold problems. Multiple owners report warranty disputes and costly out-of-pocket repairs exceeding $3,000, making this generation a risky used-car purchase.
Owners report a constellation of engine faults. The most alarming pattern is unexpected shutdown during highway driving, with the dashboard flashing "Engine Power Reduced" followed by service alerts. One owner documented four dealer visits for the same symptom over two years, with repairs addressing poor connectors, converters, ECM, and PCM reprogramming—yet the problem recurred. Another owner experienced loss of consciousness inside the cabin, allegedly from fumes, resulting in a crash.
Timing chain failure appears repeatedly, with loud rattling and stalling at highway speeds. Repair costs exceeded $3,100; the same dealership saw multiple other identical STS complaints. One owner's engine consumed 5–7 quarts every 500 miles and continued burning oil even after a full overhaul and transmission rebuild. Others reported intake/exhaust manifold failure, catalytic converter popping with cylinder misfiring, and oil leaking from crankcase gaskets at quotations around $4,150.
A strong, unidentified odor from new prompted concern about toxins; the dealer's odor-eater fix failed and GM did not respond. Lean fuel-system codes (PO171, PO174) persisted despite repeated repair attempts. One vehicle simply died with smoke from the tailpipe and refused to restart.
Warranty coverage gaps compound the damage: one owner paid out-of-pocket for a driveline repair; another's VIN was excluded from a catalytic converter warranty extension. Owners universally describe frustration with unresolved issues and safety concerns.
Same Cadillac STS engine reports on nearby years: 2006
Failure modes owners describe
Engine shutdown with "Engine Power Reduced" message
Vehicle shuts down automatically during driving, typically on highway or in traffic. Dashboard displays 'ENGINE POWER REDUCED' followed by service messages for ABS, radar, and stability control. Traction control disables before shutdown. Same owner documented four service attempts (connector repair, converter replacement, ECM replacement, PCM reprogramming) with recurring symptoms.
When: Over 2-year period; multiple episodes Feb 2008–Dec 2010
Symptoms owners cite: Engine shutdown during driving; ENGINE POWER REDUCED display message; SERVICE ANTI-LOCK BRAKE SYS message; SERVICE RADAR message; SERVICE STABILITY SYS message; Traction control automatically disabled; Check engine light on and off
Repairs/costs cited: Poor drag on C102 connector under hood (Feb 2008); catalytic converter replacement (Apr 2009); ECM replacement (Oct 2009); PCM reprogramming (May 2010)
Loss of consciousness / fumes in cabin
Driver lost consciousness for approximately 30 seconds while traveling 40 MPH, believed due to fumes entering passenger compartment. Vehicle crashed into another vehicle; airbags deployed. Dealer inspected for cabin fume leakage.
When: Single incident at 40 MPH
Symptoms owners cite: Loss of consciousness; Fumes in passenger compartment; Crash resulting from loss of consciousness
Strong toxic odor in vehicle
New vehicle had a strong, overpowering odor. Passenger's eyes watered and throat burned. Odor originated from trunk and intensified in hot weather. Dealer applied odor eaters inside trunk; owner questioned if odor was toxic. GM did not address concerns. Problem remained unresolved.
When: Present from new
Symptoms owners cite: Strong odor; Eyes watering; Throat burning; Odor stronger in heat
Repairs/costs cited: Odor eaters placed in trunk by dealer
Recalls/TSBs owners mention: GM did not answer concerns
Oil leakage through engine gaskets
Burnt oil leaking through engine gaskets between crankcase and manifold. Owner quoted $4,153 for gasket replacement; additional gaskets found during repairs, increasing total cost.
When: <UNKNOWN>
Symptoms owners cite: Oil leakage; Burnt oil visible
Repairs/costs cited: $4,153 quoted for gasket replacement; additional gaskets needed during repair
Catalytic converter popping and cylinder misfiring
Catalytic converter makes loud popping noises on passenger front side. Vehicle misfires in cylinder 1. Unexpected acceleration occurs without pedal input. GM extended catalytic converter warranty to 200,000 miles for converter problems, but owner's VIN excluded from coverage.
When: <UNKNOWN>
Symptoms owners cite: Loud popping from catalytic converter; Misfiring in cylinder 1; Unexpected acceleration without pedal input
Recalls/TSBs owners mention: GM extended catalytic converter warranty to 200,000 miles for some vehicles; owner's VIN not included
Engine misfiring and excessive oil consumption
Engine misfiring with no prior warning signs. Complete engine overhaul performed (rings, bearings replaced) at 68k–69k miles. Vehicle consumes 1 quart oil per 2,000 miles, which owner states is excessive. No low-oil warning on dashboard or DIC other than oil-life message.
When: 68,000–69,000 miles
Symptoms owners cite: Misfiring; Excessive oil consumption
Repairs/costs cited: Complete engine overhaul (rings, bearings, etc.); covered under extended warranty
Reduce Power light and loss of engine power on interstate
Two instances of Reduce Power light and loss of engine power while driving interstate. Engine would not shut off when shifted to Park three separate times; dashboard message stated 'Put in Park' despite vehicle being in Park. Driveline axle seal recall did not cover repair cost.
When: Multiple episodes; possibly after rough area on interstate
Symptoms owners cite: Reduce Power light; Loss of engine power; Engine will not shut off in Park; Dashboard message error
Repairs/costs cited: Owner paid out-of-pocket for driveline axle seal repair at Hoover, AL Cadillac dealer
Recalls/TSBs owners mention: Driveline axle seal recall would not cover cost
Timing chain failure with rattling and stalling
Loud rattling noise followed by sluggish engine and stalling while driving. Dealership diagnosed timing chain problem. Owner noted at least 3 other 2005 Cadillac STS vehicles at dealership reported identical issue. Repair cost exceeded $3,100.
When: Multiple episodes at highway speeds (55–60 MPH)
Symptoms owners cite: Loud rattling noise; Sluggish engine; Engine stalling at highway speed
Repairs/costs cited: Timing chain repair; cost over $3,100
Intake and exhaust manifold failure with power loss
Engine lost power while driving 30 MPH; check engine light illuminated. Dealership diagnosed intake and exhaust manifold failure requiring replacement. Vehicle was successfully repaired.
When: Approximately 48,000 miles
Symptoms owners cite: Engine lost power; Check engine light illuminated
Repairs/costs cited: Intake and exhaust manifold replacement
Extreme oil consumption / evaporation
Vehicle consuming 5–7 quarts of oil every 500 miles. Owner states this is abnormal consumption. Engine overhaul and transmission rebuild performed with new components; issue persists. No visible leaks or symptoms other than oil depletion. Problem remains unresolved.
When: Low mileage; persists after overhaul
Symptoms owners cite: Extreme oil consumption; Oil evaporating; No visible leaks
Repairs/costs cited: Engine overhaul and transmission rebuild with new components
Engine failure with smoke and no restart
Large ball of smoke came from tailpipe while driving. Vehicle made a loud breaking noise and shut off. Engine would not restart.
When: Single incident during initial startup
Symptoms owners cite: Large cloud of smoke from tailpipe; Loud breaking noise; Engine shutdown; No restart
Check engine light with fuel system codes
Check engine light comes on repeatedly after attempts to repair. Diagnostic codes PO171 and PO174 indicate fuel system lean condition (both banks).
When: Recurring condition
Symptoms owners cite: Check engine light
Codes mentioned: PO171, PO174
Synthesized from 12 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 5 most recent
Went outside to drive the car begin to drive off as I was driving a big ball of smoke came out the tail pipe and sounded as if something broke and the car shut off. The car would not re start. *tr
Tl* the contact owns a 2005 Cadillac sts. The contact stated while driving 30 MPH, the engine lost power as the engine light illuminated. The contact merged the vehicle to side of the road safely, which was then towed to the dealer. The technician diagnosed that the intake and exhaust manifold needed to be replaced. The vehicle was repaired. The manufacturer was not notified of the issue. The…
S10 appropriate handling- letter to the secretary from constituent re copy of a letter addressed to general motors chief executive officer mary barra regarding the recall of vehicles that can leak oil and catch fire. *smd the consumer stated the technician showed him where burnt oil had leaked through engine gaskets between the crankcase and manifold. The consumer was quoted a price of $…
Twice drive on interstate (possible after rough area on interstate) reduce power light and no engine power atlanta, ga traffic nearly got hit several times trying to get to the side of the interstate. Now three times stop car put in park and engine will not shut off, light says put in park although it is in park or should be. The recall on the drive axle seal, Cadillac would not cover cost, I…
Had engine trouble with your 2005 Cadillac STS?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the engine problem on the 2005 Cadillac STS?
It's a meaningful issue. 12 complaints have been filed and the failure mode causes operational problems for owners. Repairs average $3,100.
At what mileage does the engine typically fail?
Across the 8 complaints that reported odometer mileage, most engine failures cluster between 48,000 and 81,000 miles, with the median around 69,000. A quarter of owners report trouble before 48,000; a quarter make it past 81,000. Maintenance history matters more than the odometer alone — this is the reported failure window, not a guarantee.
What does it cost to fix?
Independent shops typically charge around $3,100 for engine repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to engine?
No active recalls currently cover engine issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2005/Cadillac/STS.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.