The 991.1 generation 911 (2012-2016) is generally reliable, but certain engine variants—particularly early 3.8L Carrera S motors—suffer from catastrophic bore scoring and IMS successor issues. The PDK transmission is robust, though cooler and mount failures occur with age.
Symptoms: Metallic ticking or knocking from engine, especially cold start, Blue smoke on startup or hard acceleration, Oil consumption exceeding 1 qt per 1,000 mi, Loss of compression in one or more cylinders
Fix: Complete engine rebuild or replacement. Requires 40-60 hours labor for engine removal, disassembly, bore sleeving or replacement, new pistons, rings, bearings, and reinstallation. Some owners opt for factory reman or aftermarket solutions.
Estimated cost: $18,000-35,000
Transmission Oil Cooler Line Leaks
Common · medium severity
Typical onset: 60,000-100,000 mi
Symptoms: ATF dripping from bellhousing area or undertray, Low transmission fluid warning, Puddles under vehicle after parking
Fix: Replace oil cooler lines and reseal connections. Access requires removal of undertray and partial exhaust work. 3-5 hours labor plus fluid refill and system bleed.
Estimated cost: $800-1,500
Transmission Mount Failure
Common · low severity
Typical onset: 70,000-120,000 mi
Symptoms: Clunking when shifting from Park to Drive or Reverse, Excessive drivetrain movement felt through chassis, Vibration at idle in gear
Fix: Replace transmission mount and inspect adjacent mounts. Requires lift access and support of transmission. 2-3 hours labor.
Estimated cost: $600-1,000
Direct Fuel Injector Carbon Buildup
Occasional · medium severity
Typical onset: 80,000-120,000 mi
Symptoms: Rough idle and misfires when cold, Hesitation or stumble during light throttle acceleration, Check engine light with misfire codes (P0300-P0306)
Fix: Walnut blast intake ports and clean injectors. Requires intake manifold removal. 6-8 hours labor for proper cleaning.
Estimated cost: $1,200-2,000
Coolant Expansion Tank Cracking
Occasional · medium severity
Typical onset: 60,000-90,000 mi
Symptoms: Coolant smell in cabin or engine bay, Low coolant warning light, Visible coolant seepage on right side of engine bay
Fix: Replace expansion tank and pressure test system. Check hoses and connections while open. 2-3 hours labor including coolant refill and bleed.
Estimated cost: $500-800
Hood Latch Mechanism Failure (NHTSA Recall)
Rare · high severity
Symptoms: Hood not latching securely or popping open, Latch feels loose or inconsistent, Hood misalignment or rattle
Fix: Recall repair involves replacing hood latch assembly. Should be covered under recall 14V-400. If not completed, dealership handles at no cost. 1-2 hours labor.
Estimated cost: $0 (recall) or $400-600 if self-pay
Owner tips
Check engine production date and VIN range against known bore scoring TSBs—2012-2013 Carrera S models are highest risk
Verify transmission cooler lines annually for seepage, especially before long trips
Use Top Tier fuel and consider periodic fuel system cleaning to combat carbon buildup on direct-injection engines
Inspect coolant expansion tank for stress cracks every oil change—cheap insurance against overheating
Budget $2,000-3,000 annually for maintenance beyond routine service; these are not Camrys
Buy a 2014+ base Carrera (3.4L) with documented service history; avoid early 3.8L cars unless engine health is proven via compression and leak-down tests—when they're good, they're great, but failures are wallet-destroying.
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: Located in front trunk; AGM required for start-stop system and electronics
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Every control module on the 2012-2017 Porsche 911 — 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.
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.
Porsche Cars North America, Inc. (Porsche) is recalling certain model year 2014-2015 Porsche 911, Boxster, and Cayman vehicles manufactured May 7, 2014, to September 23, 2014. The front hood upper lock components were not manufactured to specification and may fail to securely latch the vehicle's hood during operation.
Consequence: A failure of the hood latching mechanism may cause the hood to suddenly open during vehicle operation and will severely impede the driver's ability to see out the front windshield, increasing the risk of a vehicle crash.
Remedy: Porsche will notify owners, and dealers will replace the lock on the front hood, free of charge. The recall began December 12, 2014. Owners may contact Porsche customer service at 1-800-767-7243. Porsche's number for this recall is AE04.
Fuel economy (EPA)
City
18mpg
Highway
26mpg
Combined
21mpg
Fuel
Premium Gasoline
Capability & size
EPA class
Minicompact Cars
Wiper blades
991 generation (2012-2019). Different lengths for driver and passenger. Coupe body style has 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 2014 Porsche 911 3.8L H6 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.