Porsche 911 991
Weaknesses, engine ratings and buying advice
The Porsche 911 991 (2011–2019) is the modern water-cooled 911 that gets nearly everything right — the car that moved the 911 from sports car to genuine sports car that also works as daily transport. Two distinct sub-generations: the 991.1 (2012–2015, naturally aspirated) and 991.2 (2016–2019, twin-turbo). Different engines, different failure profiles, both worth understanding.
991.1 engines (MA1 family, naturally aspirated): The base 3.4L MA1.01/MA1.03 (Carrera, 350 hp) and 3.8L MA1.02 (Carrera S, 400 hp) eliminated the IMS bearing of older generations entirely. The intermediate shaft now runs on a pressurized oil bearing — catastrophic engine failure from IMS is not a 991 concern. What the 991.1 inherited: the piston ring oil consumption problem. Some early MA1 engines consumed up to 1 quart per 1,000 miles. Symptoms: blue smoke under acceleration, sooty right exhaust tip. Porsche addressed this progressively through the 991.1 run — 2012–2013 builds have the highest incidence, 2014–2015 are significantly improved. The belt tensioner hydraulic unit fails at approximately 60,000 miles — rust on the mounting bolt indicates imminent failure. The tensioner drives the water pump and A/C compressor; failure strands the car. Replacement: $400–900 parts and labor.
991.2 engines (twin-turbo): The 3.0L twin-turbo in the 991.2 (MA2 family, 370–420 hp) is a fundamentally different engine. Turbos add: wastegate actuator play causing a rattle at cold start (common, cosmetic, most replaced under warranty), ignition coil packs cracking under heat cycling (replace all at once — $600–1,200 for a set), and intercooler condensation in humid climates that can cause startup misfires. Water pump failures shifted to the cooling system connections — Porsche extended warranty to 10 years on some 991.2 water pump components. Oil consumption is better controlled than the 991.1 but still higher than pre-turbocharged eras.
PDK transmission: Extremely reliable mechanically, but requires genuine PDK fluid changes every 40,000 miles. The fluid is hygroscopic — absorbed moisture causes mechatronic unit corrosion and shifting hesitation. Repair: $1,500–3,000. Full PDK replacement exceeds $20,000. Any 991 with 80,000+ miles and no documented PDK fluid service is a known risk. The 7-speed manual has a characteristic notchy feel in 7th gear — not a defect, factory characteristic, improved on 991.2.
Vehicle-level issues: The active engine mounts (PADM) with Sport Chrono package develop sensor failures causing PADM warning messages and increased vibration. Replacement: $220–2,500 depending on which sensor has failed. Front AC condensers sit exposed behind the bumper — stone damage causes slow refrigerant leaks ($1,200–1,800 per condenser). Targa models: the sliding roof seal detaches at the front right, and high-pressure car washes force water past the A-pillar joint. Cabriolet models: soft-top fabric chafes at fold lines after 3–4 years and Porsche has declined warranty claims — $3,000–5,500 for full replacement. Interior rattles from door cards and parcel shelf are endemic.
GT3 and Turbo: The 991.1 GT3 with the MA1.75 naturally aspirated 3.8L had a connecting rod bolt recall — any unfixed 991.1 GT3 is a liability. Verify NHTSA recall completion via VIN before purchase, non-negotiable. The 991.1 GT3 RS had similar engine failure reports; Porsche offered extended warranty and engine replacement at dealer cost. The 991 Turbo uses a twin-turbo flat-six derived from the GT3 architecture — mechanically robust, oil consumption is lower than the Carrera engines.
Test-drive checklist: 991.1 Carrera: exhaust tip symmetry — right sooty = oil consumption. Belt tensioner: rust on mounting bolt visible on cold start inspection. PDK: fluid service history documentation. PADM: any PADM warnings on startup, vibration at idle in Sport mode? GT3: connecting rod recall confirmed? 991.2: cold start rattle (wastegate) — acceptable if intermittent and warm-idle quiet. Targa: operate full roof cycle, check seal at front right.
2026 market: 991.1 base Carrera from $65,000–90,000. Carrera S from $72,000–105,000. GTS from $85,000–120,000. Turbo from $95,000–130,000. GT3 from $140,000–220,000+. 991.2 Carrera from $75,000–100,000. Carrera S from $88,000–115,000. Turbo S from $130,000–175,000.
Insider pick: 991.1 Carrera S (2014–2015) or 991.2 Carrera (2016–2017) — the 2014–2015 cars resolved the worst piston ring issues and the 991.2 turbo Carrera is more practical without the complexity of the GTS or Turbo. Both: full service history, PDK fluid documented, belt tensioner replaced or checked. Avoid: 991.1 GT3 without recalled engine bolt confirmation, any 991 with high mileage and no PDK service.
700 PS
GT2 RS · Benzin
515 kW, Rear-Wheel, No Net
Legendary!400 PS
3.8L Benzin
5 weaknesses
Good Choice700 PS
3.8L Turbo Benzin
10 weaknesses
Stay Away!Body Variants
The Porsche 911 991 is available as Coupé and Convertible — choose your body type for specific insurance data:
Generations
Engine Overview
The Porsche 911 991 is available with 11 engine variants — from 345 to 700 hp. 10 variants had engine changes — the model year is crucial.
The 3.4-litre is the more understated sibling of the big 3.8 — less displacement, less drama, but by no means without character. It revs cleanly to 7,400 rpm and sounds pleasantly throaty without screaming. The world's first 7-speed manual gearbox in a production sports car is an interesting technical achievement, but takes getting used to in practice: the shift action is somewhat longer and notchier than the predecessor 6-speed, the throttle response however direct and honest. Reliability is at the usual high Porsche level; coolant losses at gaskets are the most common issue on older examples. In direct comparison the 3.8 has more fullness, but anyone who values light steering and clear rear axle communication gets full value here.
- !! Bore scoring on Alusil cylinders from 80,000 km
Alusil cylinder bores can score due to faulty injectors or cold-start abuse. Engine can seize. Repair cost €10,000–20,000.
Symptoms: Increased oil consumption, blue smoke on cold start, bore scoring visible on borescope - !! High-pressure fuel pump (HPFP) failure from 120,000 km
The DFI high-pressure fuel pump fails and is often unavailable for months. Poor cold starting is the early symptom.
Symptoms: Engine starts only on the third attempt, yellow engine warning light, P1024/P1026 - ! Intake valve carbon deposits from DFI from 70,000 km
Typical DFI problem: carbon deposits on the intake valves restrict flow. Walnut blasting is the fix.
Symptoms: Power loss, rough idle, occasional misfires
+ 2 more engine weaknesses + vehicle weaknesses
First turbocharged Carrera — and you can tell. Revs through more richly than any naturally aspirated Carrera before; boost build-up comes early and stays present. Technically a carefully developed engine on the proven 9A1 crankcase, but the early build years 2016–2017 brought design weaknesses: the turbo oil feed lines initially lacked check valves, the wastegate linkages corroded in humid climates. Porsche addressed both via TSB — anyone buying an early batch car should verify that the revised parts are fitted. The water pump is a known issue: internal failure without visible external leakage, coolant enters vacuum lines. 2017–2018 vehicles have 10-year warranty coverage in the US. When buying: check service history and coolant level, look for smoke traces on cold start.
- !! Water pump failure with internal coolant loss from 60,000 km
The MA2.01 water pump fails internally — coolant enters the vacuum lines without any external visible leak. Porsche issued a 10-year warranty extension for 2017–2018 (USA/Canada only).
Symptoms: Coolant warning light at operating temperature, temperature spikes above 115°C, coolant level dropping without visible leak, sweet smell after driving - !! Turbo oil feed pipe failure from 50,000 km
Missing check valves in the turbo oil feed line allow oil backflow. Aluminium swarf from production in the oil tank worsens the damage. Porsche issued revised lines via TSB.
Symptoms: Blue smoke on cold start, power loss, turbo only makes full boost on one side - !! Wastegate actuator corrosion and seizure from 55,000 km
The wastegate linkage on early 991.2 cars corrodes and seizes. Metallic rattling on cold start is an early warning sign. Revised actuators with better sealing from 2018.
Symptoms: Metallic rattle on cold start, uneven boost build-up, engine fault warning light, power drop under high load
+ 4 more engine weaknesses + vehicle weaknesses
The 3.4-litre is the more understated sibling of the big 3.8 — less displacement, less drama, but by no means without character. It revs cleanly to 7,400 rpm and sounds pleasantly throaty without screaming. The world's first 7-speed manual gearbox in a production sports car is an interesting technical achievement, but takes getting used to in practice: the shift action is somewhat longer and notchier than the predecessor 6-speed, the throttle response however direct and honest. Reliability is at the usual high Porsche level; coolant losses at gaskets are the most common issue on older examples. In direct comparison the 3.8 has more fullness, but anyone who values light steering and clear rear axle communication gets full value here.
- !! Bore scoring on Alusil cylinders from 80,000 km
Alusil cylinder bores can score due to faulty injectors or cold-start abuse. Engine can seize. Repair cost €10,000–20,000.
Symptoms: Increased oil consumption, blue smoke on cold start, bore scoring visible on borescope - !! High-pressure fuel pump (HPFP) failure from 120,000 km
The DFI high-pressure fuel pump fails and is often unavailable for months. Poor cold starting is the early symptom.
Symptoms: Engine starts only on the third attempt, yellow engine warning light, P1024/P1026 - ! Intake valve carbon deposits from DFI from 70,000 km
Typical DFI problem: carbon deposits on the intake valves restrict flow. Walnut blasting is the fix.
Symptoms: Power loss, rough idle, occasional misfires
+ 2 more engine weaknesses + vehicle weaknesses
First turbocharged Carrera — and you can tell. Revs through more richly than any naturally aspirated Carrera before; boost build-up comes early and stays present. Technically a carefully developed engine on the proven 9A1 crankcase, but the early build years 2016–2017 brought design weaknesses: the turbo oil feed lines initially lacked check valves, the wastegate linkages corroded in humid climates. Porsche addressed both via TSB — anyone buying an early batch car should verify that the revised parts are fitted. The water pump is a known issue: internal failure without visible external leakage, coolant enters vacuum lines. 2017–2018 vehicles have 10-year warranty coverage in the US. When buying: check service history and coolant level, look for smoke traces on cold start.
- !! Water pump failure with internal coolant loss from 60,000 km
The MA2.01 water pump fails internally — coolant enters the vacuum lines without any external visible leak. Porsche issued a 10-year warranty extension for 2017–2018 (USA/Canada only).
Symptoms: Coolant warning light at operating temperature, temperature spikes above 115°C, coolant level dropping without visible leak, sweet smell after driving - !! Turbo oil feed pipe failure from 50,000 km
Missing check valves in the turbo oil feed line allow oil backflow. Aluminium swarf from production in the oil tank worsens the damage. Porsche issued revised lines via TSB.
Symptoms: Blue smoke on cold start, power loss, turbo only makes full boost on one side - !! Wastegate actuator corrosion and seizure from 55,000 km
The wastegate linkage on early 991.2 cars corrodes and seizes. Metallic rattling on cold start is an early warning sign. Revised actuators with better sealing from 2018.
Symptoms: Metallic rattle on cold start, uneven boost build-up, engine fault warning light, power drop under high load
+ 4 more engine weaknesses + vehicle weaknesses
The MA1.01 of the 997.2 Carrera S 3.8 DFI is the most powerful naturally aspirated variant of the 997 range — 283 kW in the Carrera S, 300 kW in GTS configuration. Direct injection, no IMS, higher compression, higher rev potential. Sonically similar to the MA1.02 — silkier, slightly less raw than the M97.01, but with a finer pull in the upper rev range. The 997.2 is regarded as "the most refined 997" — better in almost everything except emotional sound. Upgraded with a sport exhaust the engine sound is respectable; stock it remains more subdued than the emotional M97.01. For daily use or regular track days, the MA1.01 is the most relaxed naturally aspirated engine of the range.
- !! Bore scoring on Alusil cylinders from 80,000 km
Alusil cylinder bores can score due to faulty injectors or cold-start abuse. Engine can seize. Repair cost €10,000–20,000.
Symptoms: Increased oil consumption, blue smoke on cold start, bore scoring visible on borescope - !! Elevated oil consumption from DFI piston rings from 85,000 km
Higher output and rev-happy nature of the 3.6L accelerate piston ring wear. Oil consumption above 0.5L/1000km from around 80,000 km is not unusual.
Symptoms: Oil level warning, blue-tinged exhaust smoke under high load or on cold start - !! High-pressure fuel pump (HPFP) failure from 120,000 km
The DFI high-pressure fuel pump fails and is often unavailable for months. Poor cold starting is the early symptom.
Symptoms: Engine starts only on the third attempt, yellow engine warning light, P1024/P1026
+ 3 more engine weaknesses + vehicle weaknesses
The MA2.03 is technically the MA2.01 with a higher-rated boost controller — mechanically the same base, but the wider boost window brings more thermal load to the turbochargers. Reliable when maintained, but the structural weaknesses of the early MA2 programme hit harder here: turbo oil feed lines without check valves, wastegate linkage corrosion — both addressed via TSB, check build year. GTS models have reported particularly many turbo failures at the input shaft seal. Anyone buying a pre-2018 example should insist on confirmation that the revised oil lines are fitted. Water pump failure — same weakness as the MA2.01. The MA2.03 in the GTS with manual gearbox is one of the most emotional Carreras of all time — the effort for conscientious maintenance is worth it.
- !! Water pump failure with internal coolant loss from 60,000 km
Identical problem to MA2.01 — the water pump fails internally and coolant enters the vacuum lines. Porsche 10-year warranty for 2017–2018 (USA/Canada only).
Symptoms: Coolant warning light, temperature spikes above 115°C, coolant level dropping without visible leak - !! Turbo oil feed pipe failure from 50,000 km
Same oil feed issue as MA2.01 — at higher boost pressure the consequences are more severe. GTS models particularly affected. Porsche issued revised lines via TSB.
Symptoms: Blue smoke on cold start, power loss, turbo only makes full boost on one side - !! Turbo shaft seal failure from 55,000 km
On higher-output MA2.03 variants (GTS, 4S), turbo shaft seals fail under greater thermal stress. Oil escapes into the intake system.
Symptoms: Blue smoke from exhaust, oil in intake tract, measurably rising oil consumption, power loss
+ 4 more engine weaknesses + vehicle weaknesses
3.8 litres, DFI direct injection, up to 7,800 rpm — the MA1.03 is the thoroughbred naturally aspirated engine of the 991.1 generation. The power build-up is emphatically linear, no torque plateau, no turbo lag, just an evenly rising surge that doesn't relent to the redline. In the upper rev range it sounds — except for the Mezger derivative — as sharp as no other modern mass-production boxer. Compared to the subsequent biturbo it lacks the spontaneous part-load response, but anyone who's been above 6,000 rpm in the 3.8 doesn't miss much. Technically robust, coolant issues identical to the 3.4 — not a real concern on well-maintained examples.
- !! Bore scoring on Alusil cylinders from 80,000 km
Alusil cylinder bores can score due to faulty injectors or cold-start abuse. Engine can seize. Repair cost €10,000–20,000.
Symptoms: Increased oil consumption, blue smoke on cold start, bore scoring visible on borescope - !! High-pressure fuel pump (HPFP) failure from 120,000 km
The DFI high-pressure fuel pump fails and is often unavailable for months. Poor cold starting is the early symptom.
Symptoms: Engine starts only on the third attempt, yellow engine warning light, P1024/P1026 - ! Intake valve carbon deposits from 60,000 km
High-revving 3.8L DFI engine with typical intake valve carbonisation. Walnut blasting every 60,000 km recommended.
Symptoms: Noticeable power loss, uneven idle
+ 2 more engine weaknesses + vehicle weaknesses
The MA2.03 is technically the MA2.01 with a higher-rated boost controller — mechanically the same base, but the wider boost window brings more thermal load to the turbochargers. Reliable when maintained, but the structural weaknesses of the early MA2 programme hit harder here: turbo oil feed lines without check valves, wastegate linkage corrosion — both addressed via TSB, check build year. GTS models have reported particularly many turbo failures at the input shaft seal. Anyone buying a pre-2018 example should insist on confirmation that the revised oil lines are fitted. Water pump failure — same weakness as the MA2.01. The MA2.03 in the GTS with manual gearbox is one of the most emotional Carreras of all time — the effort for conscientious maintenance is worth it.
- !! Water pump failure with internal coolant loss from 60,000 km
Identical problem to MA2.01 — the water pump fails internally and coolant enters the vacuum lines. Porsche 10-year warranty for 2017–2018 (USA/Canada only).
Symptoms: Coolant warning light, temperature spikes above 115°C, coolant level dropping without visible leak - !! Turbo oil feed pipe failure from 50,000 km
Same oil feed issue as MA2.01 — at higher boost pressure the consequences are more severe. GTS models particularly affected. Porsche issued revised lines via TSB.
Symptoms: Blue smoke on cold start, power loss, turbo only makes full boost on one side - !! Turbo shaft seal failure from 55,000 km
On higher-output MA2.03 variants (GTS, 4S), turbo shaft seals fail under greater thermal stress. Oil escapes into the intake system.
Symptoms: Blue smoke from exhaust, oil in intake tract, measurably rising oil consumption, power loss
+ 4 more engine weaknesses + vehicle weaknesses
The MA1.01 of the 997.2 Carrera S 3.8 DFI is the most powerful naturally aspirated variant of the 997 range — 283 kW in the Carrera S, 300 kW in GTS configuration. Direct injection, no IMS, higher compression, higher rev potential. Sonically similar to the MA1.02 — silkier, slightly less raw than the M97.01, but with a finer pull in the upper rev range. The 997.2 is regarded as "the most refined 997" — better in almost everything except emotional sound. Upgraded with a sport exhaust the engine sound is respectable; stock it remains more subdued than the emotional M97.01. For daily use or regular track days, the MA1.01 is the most relaxed naturally aspirated engine of the range.
- !! Bore scoring on Alusil cylinders from 80,000 km
Alusil cylinder bores can score due to faulty injectors or cold-start abuse. Engine can seize. Repair cost €10,000–20,000.
Symptoms: Increased oil consumption, blue smoke on cold start, bore scoring visible on borescope - !! Elevated oil consumption from DFI piston rings from 85,000 km
Higher output and rev-happy nature of the 3.6L accelerate piston ring wear. Oil consumption above 0.5L/1000km from around 80,000 km is not unusual.
Symptoms: Oil level warning, blue-tinged exhaust smoke under high load or on cold start - !! High-pressure fuel pump (HPFP) failure from 120,000 km
The DFI high-pressure fuel pump fails and is often unavailable for months. Poor cold starting is the early symptom.
Symptoms: Engine starts only on the third attempt, yellow engine warning light, P1024/P1026
+ 3 more engine weaknesses + vehicle weaknesses
The MA2.03 is technically the MA2.01 with a higher-rated boost controller — mechanically the same base, but the wider boost window brings more thermal load to the turbochargers. Reliable when maintained, but the structural weaknesses of the early MA2 programme hit harder here: turbo oil feed lines without check valves, wastegate linkage corrosion — both addressed via TSB, check build year. GTS models have reported particularly many turbo failures at the input shaft seal. Anyone buying a pre-2018 example should insist on confirmation that the revised oil lines are fitted. Water pump failure — same weakness as the MA2.01. The MA2.03 in the GTS with manual gearbox is one of the most emotional Carreras of all time — the effort for conscientious maintenance is worth it.
- !! Water pump failure with internal coolant loss from 60,000 km
Identical problem to MA2.01 — the water pump fails internally and coolant enters the vacuum lines. Porsche 10-year warranty for 2017–2018 (USA/Canada only).
Symptoms: Coolant warning light, temperature spikes above 115°C, coolant level dropping without visible leak - !! Turbo oil feed pipe failure from 50,000 km
Same oil feed issue as MA2.01 — at higher boost pressure the consequences are more severe. GTS models particularly affected. Porsche issued revised lines via TSB.
Symptoms: Blue smoke on cold start, power loss, turbo only makes full boost on one side - !! Turbo shaft seal failure from 55,000 km
On higher-output MA2.03 variants (GTS, 4S), turbo shaft seals fail under greater thermal stress. Oil escapes into the intake system.
Symptoms: Blue smoke from exhaust, oil in intake tract, measurably rising oil consumption, power loss
+ 4 more engine weaknesses + vehicle weaknesses
3.8 litres, DFI direct injection, up to 7,800 rpm — the MA1.03 is the thoroughbred naturally aspirated engine of the 991.1 generation. The power build-up is emphatically linear, no torque plateau, no turbo lag, just an evenly rising surge that doesn't relent to the redline. In the upper rev range it sounds — except for the Mezger derivative — as sharp as no other modern mass-production boxer. Compared to the subsequent biturbo it lacks the spontaneous part-load response, but anyone who's been above 6,000 rpm in the 3.8 doesn't miss much. Technically robust, coolant issues identical to the 3.4 — not a real concern on well-maintained examples.
- !! Bore scoring on Alusil cylinders from 80,000 km
Alusil cylinder bores can score due to faulty injectors or cold-start abuse. Engine can seize. Repair cost €10,000–20,000.
Symptoms: Increased oil consumption, blue smoke on cold start, bore scoring visible on borescope - !! High-pressure fuel pump (HPFP) failure from 120,000 km
The DFI high-pressure fuel pump fails and is often unavailable for months. Poor cold starting is the early symptom.
Symptoms: Engine starts only on the third attempt, yellow engine warning light, P1024/P1026 - ! Intake valve carbon deposits from 60,000 km
High-revving 3.8L DFI engine with typical intake valve carbonisation. Walnut blasting every 60,000 km recommended.
Symptoms: Noticeable power loss, uneven idle
+ 2 more engine weaknesses + vehicle weaknesses
The MA2.03 is technically the MA2.01 with a higher-rated boost controller — mechanically the same base, but the wider boost window brings more thermal load to the turbochargers. Reliable when maintained, but the structural weaknesses of the early MA2 programme hit harder here: turbo oil feed lines without check valves, wastegate linkage corrosion — both addressed via TSB, check build year. GTS models have reported particularly many turbo failures at the input shaft seal. Anyone buying a pre-2018 example should insist on confirmation that the revised oil lines are fitted. Water pump failure — same weakness as the MA2.01. The MA2.03 in the GTS with manual gearbox is one of the most emotional Carreras of all time — the effort for conscientious maintenance is worth it.
- !! Water pump failure with internal coolant loss from 60,000 km
Identical problem to MA2.01 — the water pump fails internally and coolant enters the vacuum lines. Porsche 10-year warranty for 2017–2018 (USA/Canada only).
Symptoms: Coolant warning light, temperature spikes above 115°C, coolant level dropping without visible leak - !! Turbo oil feed pipe failure from 50,000 km
Same oil feed issue as MA2.01 — at higher boost pressure the consequences are more severe. GTS models particularly affected. Porsche issued revised lines via TSB.
Symptoms: Blue smoke on cold start, power loss, turbo only makes full boost on one side - !! Turbo shaft seal failure from 55,000 km
On higher-output MA2.03 variants (GTS, 4S), turbo shaft seals fail under greater thermal stress. Oil escapes into the intake system.
Symptoms: Blue smoke from exhaust, oil in intake tract, measurably rising oil consumption, power loss
+ 4 more engine weaknesses + vehicle weaknesses
3.8-litre biturbo, 9:1 compression, turbochargers with 67 mm compressor wheel (vs. 58 mm on the Turbo S), collectors with 25% enlarged cross-section. This is not a detuned Turbo S but an engine with bespoke pistons, modified crankcase and complete intercooler rebuild. The water-based intercooler spray is functional but capacity-limited — on track the reservoir empties quickly, after which the ECU limits power. Oil capacity at 7.94 litres is significantly higher than the GT3 (6.4 L), reflecting the thermal demands. The known warranty topics of the 991.1 GT3 (rocker arms, con-rod bolts) don't affect the MDH.NA — the turbo architecture is different. Reliability in daily use is well documented; high-load track use demands strict maintenance discipline.
- !! Finger Follower Metallurgy Defect — High-Rev Operation from 20,000 km
The 991.1 GT3 and GT3 RS show sub-surface material defects in the finger follower rocker components. Above 8,000 rpm, accelerated wear develops and can lead to engine damage.
Symptoms: Misfires at high revs, engine stumble above 7,500 rpm, check engine light - !! Connecting Rod Bolt Manufacturing Defect — Engine Failure from 15,000 km
Early 991.1 GT3 units (including RS) showed manufacturing defects in the connecting rod bolts. If a bolt fails, the rod breaks and the pistons punch through the block — catastrophic total engine loss.
Symptoms: Abrupt engine shutdown with loud bang, damaged engine block, sudden oil loss - !! Intercooler Water Spray — Insufficient Tank Capacity
The intercooler water spray tank is insufficient for intense track use. Once empty, the ECU automatically reduces power to prevent overheating.
Symptoms: Noticeable power reduction after several hot laps, elevated charge air temperatures, low water level warning
+ 7 more engine weaknesses + vehicle weaknesses
3.8 litres, port injection, 9,000 rpm rev limiter — this is not a daily engine. Flat-profile con-rods from forged titanium, dry sump with separate oil reservoir, variable valve timing on both banks. The early E-engines (build year 2013–2014) had con-rod bolt problems: Porsche replaced all affected vehicles with new engines. The F-engines (from 2015) saw rocker arm and camshaft wear — a metallurgical defect in certain batches. Porsche offered a 10-year warranty and revised parts. Above 7,000 rpm everything changes — refinement and character are unmatched in this class. Oil change discipline is paramount: Mobil 1 0W-40 or equivalent fully synthetic, intervals strictly maintained. Oil level note: measurement tolerance is extremely tight — even 200-300 ml over max triggers the overfill warning. Short trips, parking on a slope, or a workshop overfill of 0.3 l is enough. Top up only in 20 ml increments (Rennlist consensus).
- !! Recall: connecting rod bolts come loose (2013–2014) from 5,000 km
Connecting rod bolts can loosen and damage the crankcase. Oil escaping onto hot components creates a fire risk. Affected: 785 vehicles worldwide, model years 2013–2014 (E-engines). Porsche replaced complete engines.
Symptoms: Oil pressure warning light, unusual engine noises, visible oil mist, engine fire in extreme cases - !! Finger follower and camshaft wear (F-engines) from 65,000 km
A metallurgical defect in certain finger follower batches causes accelerated wear. Also occurs in revised F-engines. Porsche offered a 10-year warranty and updated parts.
Symptoms: Misfire at 7,250 rpm, check engine light, rough running in the upper rev range - !! Cylinder wall bore scoring from 80,000 km
The aluminium-silicon bore coating can break down, especially during cold starts in extreme cold. Piston seizure and total engine failure. Once started, the damage is irreversible.
Symptoms: Excessive oil consumption, misfires, contaminated lambda sensors, sooty exhaust on one side
+ 2 more engine weaknesses + vehicle weaknesses
4.0 litres, naturally aspirated flat-six architecture, 9,000 rpm. The MDG.GA is the final evolution of the high-revving NA line: revised combustion chamber geometry, improved valve timing over the MA1.75, and oil supply made more robust through increased oil pressure. The dry sump system demands consistent oil monitoring — consumption of 0.5–1.5 litres per 1,000 km on track is normal and not a defect sign. Check oil level regularly under intensive track use. The early 718 engine variants had a 2021 recall for defective con-rods. The lash cap issue from the 991.1 generation can also occur in the MDG.GA — Porsche built RS engines with oil pumps without protective screens. Oil changes every 15,000 km or annually, fully synthetic, and regular borescoping when buying used. Oil level note: measurement tolerance is extremely tight — even 200-300 ml over max triggers the overfill warning. Short trips, parking on a slope, or a workshop overfill of 0.3 l is enough. Top up only in 20 ml increments (Rennlist consensus).
- !! Recall: defective connecting rods (718, 2021 batch)
A supplier delivered defective connecting rods that do not meet quality specifications. Fracture is possible, leading to engine damage and elevated fire risk. 190 vehicles affected.
Symptoms: Sudden engine failure, engine oil ejection, elevated fire risk — often without warning - !! Lash cap detaches — oil pump blocks from 15,000 km
Valve lash caps on RS variants can detach due to harmonic valvetrain vibrations, drop into the sump and immediately block the unprotected oil pump. Engine failure is unavoidable.
Symptoms: Sudden oil pressure drop at 3,750–20,000 km, oil pressure warning light, engine shutdown - !! Elevated oil consumption during track use
The 4.0L naturally aspirated engine consumes 0.5–1.5 litres per 1,000 km during intensive track use. Not checking oil before and after track sessions leads to oil starvation and consequential damage.
Symptoms: Dropping oil level without visible leak, occasional oil pressure warning at high-rpm operation
+ 2 more engine weaknesses + vehicle weaknesses
3.8 litres, port injection, 9,000 rpm rev limiter — this is not a daily engine. Flat-profile con-rods from forged titanium, dry sump with separate oil reservoir, variable valve timing on both banks. The early E-engines (build year 2013–2014) had con-rod bolt problems: Porsche replaced all affected vehicles with new engines. The F-engines (from 2015) saw rocker arm and camshaft wear — a metallurgical defect in certain batches. Porsche offered a 10-year warranty and revised parts. Above 7,000 rpm everything changes — refinement and character are unmatched in this class. Oil change discipline is paramount: Mobil 1 0W-40 or equivalent fully synthetic, intervals strictly maintained. Oil level note: measurement tolerance is extremely tight — even 200-300 ml over max triggers the overfill warning. Short trips, parking on a slope, or a workshop overfill of 0.3 l is enough. Top up only in 20 ml increments (Rennlist consensus).
- !! Recall: connecting rod bolts come loose (2013–2014) from 5,000 km
Connecting rod bolts can loosen and damage the crankcase. Oil escaping onto hot components creates a fire risk. Affected: 785 vehicles worldwide, model years 2013–2014 (E-engines). Porsche replaced complete engines.
Symptoms: Oil pressure warning light, unusual engine noises, visible oil mist, engine fire in extreme cases - !! Finger follower and camshaft wear (F-engines) from 65,000 km
A metallurgical defect in certain finger follower batches causes accelerated wear. Also occurs in revised F-engines. Porsche offered a 10-year warranty and updated parts.
Symptoms: Misfire at 7,250 rpm, check engine light, rough running in the upper rev range - !! Cylinder wall bore scoring from 80,000 km
The aluminium-silicon bore coating can break down, especially during cold starts in extreme cold. Piston seizure and total engine failure. Once started, the damage is irreversible.
Symptoms: Excessive oil consumption, misfires, contaminated lambda sensors, sooty exhaust on one side
+ 2 more engine weaknesses + vehicle weaknesses
4.0 litres, naturally aspirated flat-six architecture, 9,000 rpm. The MDG.GA is the final evolution of the high-revving NA line: revised combustion chamber geometry, improved valve timing over the MA1.75, and oil supply made more robust through increased oil pressure. The dry sump system demands consistent oil monitoring — consumption of 0.5–1.5 litres per 1,000 km on track is normal and not a defect sign. Check oil level regularly under intensive track use. The early 718 engine variants had a 2021 recall for defective con-rods. The lash cap issue from the 991.1 generation can also occur in the MDG.GA — Porsche built RS engines with oil pumps without protective screens. Oil changes every 15,000 km or annually, fully synthetic, and regular borescoping when buying used. Oil level note: measurement tolerance is extremely tight — even 200-300 ml over max triggers the overfill warning. Short trips, parking on a slope, or a workshop overfill of 0.3 l is enough. Top up only in 20 ml increments (Rennlist consensus).
- !! Recall: defective connecting rods (718, 2021 batch)
A supplier delivered defective connecting rods that do not meet quality specifications. Fracture is possible, leading to engine damage and elevated fire risk. 190 vehicles affected.
Symptoms: Sudden engine failure, engine oil ejection, elevated fire risk — often without warning - !! Lash cap detaches — oil pump blocks from 15,000 km
Valve lash caps on RS variants can detach due to harmonic valvetrain vibrations, drop into the sump and immediately block the unprotected oil pump. Engine failure is unavoidable.
Symptoms: Sudden oil pressure drop at 3,750–20,000 km, oil pressure warning light, engine shutdown - !! Elevated oil consumption during track use
The 4.0L naturally aspirated engine consumes 0.5–1.5 litres per 1,000 km during intensive track use. Not checking oil before and after track sessions leads to oil starvation and consequential damage.
Symptoms: Dropping oil level without visible leak, occasional oil pressure warning at high-rpm operation
+ 2 more engine weaknesses + vehicle weaknesses
The MA1.71 is the first 991 Turbo: 3.8L biturbo on the new 9A1 crankcase, no Mezger lineage anymore. The move away from the GT1 block solves the coolant pipe adhesive problem — but brings new quirks. The engine is more compact, more rev-happy and thermally more balanced than its predecessor. VTG turbochargers remain a Porsche exclusive: no turbo lag, linear power delivery from just under 2,000 rpm. Direct injection still means valve coking over time. The early 991.1s had a weakness on the right turbo-to-intercooler hose, which Porsche fixed with a revised part number. HPFP failure and bore scoring are rare, but should be ruled out via borescope and oil analysis when buying used.
- !! High-pressure fuel pump (HPFP) failure from 80,000 km
DFI high-pressure fuel pump on the left cam drive fails internally. Fuel pressure drops, engine management switches to limp mode. Replacement parts are hard to source.
Symptoms: Extended cranking, engine briefly runs then dies, 'Engine power reduced', fault code P1023 - !! Bore scoring on Alusil cylinders
The 9A1 engine with Alusil coating shows bore scoring less often than the M97 but remains susceptible — particularly at cold starts below -10 °C and with dirty injectors.
Symptoms: Rhythmic knocking (engine noise), increased oil consumption, misfires, sooty right exhaust side, aluminium particles in oil filter - !! PDK distance sensor / valve block failure from 90,000 km
PDK distance sensor puts the gearbox into limp mode. Porsche's standard fix is a full gearbox swap — specialists repair just the sensor for significantly less.
Symptoms: Fault codes P1731–P1734, no reverse gear, gearbox limp mode, 'Transmission fault' display
+ 5 more engine weaknesses + vehicle weaknesses
Evolution of the 991 Turbo biturbo with higher boost and further optimised thermodynamics — Porsche did quiet but consistent work here. At 397 kW in the Turbo and 427 kW in the Turbo S of the 991.2 generation, it's among the most power-dense engines from Zuffenhausen. The character is similar to the MA1.71: powerful, controllable, sonically more restrained than stirred up. What distinguishes the MDA.BA from the predecessor is the even greater availability of torque — the turbos spool faster, the power build-up is more linear. As a pure powertrain this is one of the most competent turbo engines in the entire sports car segment. Reliability at the usual high Porsche level.
- !! Premature water pump failure from 30,000 km
Same water pump issue as MA2.01/MA2.03. Porsche extended warranty to 10 years. Particularly model years 2016–2018.
Symptoms: Coolant loss, overheating warning, leak at lower hoses - !! Turbo oil return lines leaking from 30,000 km
The oil return lines on the large turbos (67 mm compressor wheel) develop leaks at connection points due to pressure spikes. Oil loss can become dangerous during high-performance operation.
Symptoms: Blue smoke from engine bay, oil spots under the car, oil visible in charge air system - !! Piston and cylinder wall damage under extreme track use
The GT2 RS bespoke pistons are built for maximum power. Insufficient cooling or incorrect oil temperature can cause piston seizure. Engine damage costs over €100,000.
Symptoms: Sudden power loss, metallic noises from engine, oil pressure drop, engine stuttering
+ 7 more engine weaknesses + vehicle weaknesses
The MA1.71S differs from the MA1.71 primarily through different turbochargers, higher boost pressure and PASM Sport as standard. The crankcase and fundamental construction are identical to the 520 hp engine — both variants share weaknesses almost completely. The higher boost stresses VTG mechanics and valve train more heavily. The HPFP is identical and fails at comparable rates. What distinguishes the engine: at identical dimensions you feel more torque and spontaneity — the difference is real but subtle. Anyone buying a used Turbo S should pay special attention to engine oil quality, borescope on cylinders 4–6 and VTG actuator freedom of movement, beyond the usual MA1 checkpoints.
- !! High-pressure fuel pump (HPFP) failure from 80,000 km
Same HPFP as the MA1.71, identical failure pattern. Fuel pressure collapses, limp mode is activated. Long lead times for replacement parts.
Symptoms: Extended cranking, engine starts briefly then stalls, 'Engine power reduced', fault code P1023 - !! Bore scoring on Alusil cylinders
Despite the 9A1 block with improved Alusil coating, bore scoring is documented. The Turbo S's higher boost pressure can marginally increase risk on cold starts.
Symptoms: Rhythmic engine noise, increased oil consumption, sooty right exhaust side, aluminium particles in oil filter - !! PDK distance sensor / valve block failure from 90,000 km
PDK sensor failure puts the gearbox in limp mode. Specialists can replace just the distance sensor — considerably cheaper than the full gearbox swap Porsche typically proposes.
Symptoms: P1731–P1734, no reverse gear, gearbox limp mode
+ 5 more engine weaknesses + vehicle weaknesses
Evolution of the 991 Turbo biturbo with higher boost and further optimised thermodynamics — Porsche did quiet but consistent work here. At 397 kW in the Turbo and 427 kW in the Turbo S of the 991.2 generation, it's among the most power-dense engines from Zuffenhausen. The character is similar to the MA1.71: powerful, controllable, sonically more restrained than stirred up. What distinguishes the MDA.BA from the predecessor is the even greater availability of torque — the turbos spool faster, the power build-up is more linear. As a pure powertrain this is one of the most competent turbo engines in the entire sports car segment. Reliability at the usual high Porsche level.
- !! Premature water pump failure from 30,000 km
Same water pump issue as MA2.01/MA2.03. Porsche extended warranty to 10 years. Particularly model years 2016–2018.
Symptoms: Coolant loss, overheating warning, leak at lower hoses - !! Turbo oil return lines leaking from 30,000 km
The oil return lines on the large turbos (67 mm compressor wheel) develop leaks at connection points due to pressure spikes. Oil loss can become dangerous during high-performance operation.
Symptoms: Blue smoke from engine bay, oil spots under the car, oil visible in charge air system - !! Piston and cylinder wall damage under extreme track use
The GT2 RS bespoke pistons are built for maximum power. Insufficient cooling or incorrect oil temperature can cause piston seizure. Engine damage costs over €100,000.
Symptoms: Sudden power loss, metallic noises from engine, oil pressure drop, engine stuttering
+ 7 more engine weaknesses + vehicle weaknesses
Vehicle Weaknesses
| Weakness | Cost | |
|---|---|---|
| Soft-Top Fabric Chafes — Porsche Refuses Warranty The soft-top fabric shows pronounced chafe marks at the fold lines after 3–4 years. Porsche Germany classifies this as normal appearance. New roof approximately €4,100 plus €1,000 fitting. Symptoms: Clearly visible chafe marks and colour changes on the soft-top fabric, especially at fold lines. Headliner can come loose. from 50,000 km | High | |
| Cabriolet Roof Headliner Creasing The interior headliner of the cabriolet roof develops creases and partially detaches. A cosmetic issue with no functional impact. Symptoms: Visible creases in the roof headliner, fabric coming loose in places from 60,000 km | High | |
| Water Ingress Through Aged Seals Door and window seals harden over time. Water enters the interior in heavy rain. Symptoms: Wet footwell after heavy rain, fogged windows from 80,000 km | Low | |
| Targa Sliding Roof Seal Detaches Repeatedly — Front Right The front right seal detaches over approximately 20 cm. Re-gluing does not hold permanently. Repair requires a complete sliding roof replacement with repainting. Symptoms: Visibly protruding rubber seal front right on the Targa roof. Slight water ingress after rain. Wind noise at motorway speed. from 30,000 km | Medium | |
| Targa Roof Leaks Water in High-Pressure Car Wash High-pressure car washes force water in at the A-pillar/roof joint. Sealed in normal driving and rain. Regular seal conditioning helps. Symptoms: Water droplets on the inside of the windscreen after a car wash. Only at high water pressure, not in normal rain. | Low | |
| Gorilla-Glass rear window cracking (991.2 GT3 RS only) 991.2 GT3 RS (2018-2019) uses Gorilla Glass for the rear window. Documented cracking — Porsche ran a recall/goodwill process. 991.1 GT3 RS uses polycarbonate and is not affected. Out-of-warranty cost ~€1,000-2,500. Symptoms: Crack in rear glass, often starting at the corners, no direct impact. | High |
Test Reports
TÜV Report 2025
The 991 takes 1st place across all age categories in the TÜV ranking. Even ten-year-old examples still achieve 91% fault-free status.
2024-11Top Reported Issues
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Explore more
Known Problems and Issues +
A total of 119 weaknesses have been documented for the Porsche 911 991 (2011–2019) — 107 engine-related and 12 vehicle-related. One problem engine: MDH.NA (3.8L Turbo). Typical issues affect Body, Brakes, HVAC, Rust. Considered reliable: MA1.04 (3.4L), MA1.03 (3.8L).
911 (MA1.02, 2008–2012) — Be Careful: Bore scoring on Alusil cylinders, Elevated oil consumption from DFI piston rings, High-pressure fuel pump (HPFP) failure. Power: 345 PS.
911 (MA1.01, 2008–2012) — Be Careful: Bore scoring on Alusil cylinders, Elevated oil consumption from DFI piston rings, High-pressure fuel pump (HPFP) failure. Power: 381–385 PS.
911 (M97.77, 2009–2012) — Be Careful: Coolant pipes detach (GT1 block), Timing chain guide rails worn, Variocam actuator bolts loosen (MY2010/2011). Power: 430–435 PS.
911 (M97.77, 2009–2012) — Be Careful: Coolant pipes detach (GT1 block), Timing chain guide rails worn, Variocam actuator bolts loosen (MY2010/2011). Power: 450 PS.
911 (MA1.70, 2009–2012) — Be Careful: Coolant pipes detach from GT1 block, VTG housing corrosion, High-pressure fuel pump (HPFP) failure. Power: 500 PS.
911 (M97.70S, 2010–2012) — Be Careful: Plastic coolant pipes at oil cooler fracture, VTG linkage seized, Hydraulic engine mount leaking or collapsed. Power: 620 PS.
911 (MA1.01, 2010–2012) — Be Careful: Bore scoring on Alusil cylinders, Elevated oil consumption from DFI piston rings, High-pressure fuel pump (HPFP) failure. Power: 408 PS.
911 (MA1.70, 2010–2012) — Be Careful: Coolant pipes detach from GT1 block, VTG housing corrosion, High-pressure fuel pump (HPFP) failure. Power: 530 PS.
911 (MA1.75, 2013–2016) — Be Careful: Recall: connecting rod bolts come loose (2013–2014), Finger follower and camshaft wear (F-engines), Cylinder wall bore scoring. Power: 476 PS.
911 (MA1.71, 2013–2016) — Be Careful: High-pressure fuel pump (HPFP) failure, Bore scoring on Alusil cylinders, PDK distance sensor / valve block failure. Power: 521 PS.
911 (MA1.71S, 2013–2016) — Be Careful: High-pressure fuel pump (HPFP) failure, Bore scoring on Alusil cylinders, PDK distance sensor / valve block failure. Power: 560 PS.
911 (MA1.01, 2014–2016) — Be Careful: Bore scoring on Alusil cylinders, Elevated oil consumption from DFI piston rings, High-pressure fuel pump (HPFP) failure. Power: 430–435 PS.
911 (MA1.75, 2015–2016) — Be Careful: Recall: connecting rod bolts come loose (2013–2014), Finger follower and camshaft wear (F-engines), Cylinder wall bore scoring. Power: 500 PS.
911 (MA2.01, 2015–2019) — Be Careful: Water pump failure with internal coolant loss, Turbo oil feed pipe failure, Wastegate actuator corrosion and seizure. Power: 370 PS.
911 (MA2.03, 2015–2019) — Be Careful: Water pump failure with internal coolant loss, Turbo oil feed pipe failure, Turbo shaft seal failure. Power: 420 PS.
911 (MDA.BA, 2015–2019) — Be Careful: Premature water pump failure, Turbo oil return lines leaking, Piston and cylinder wall damage under extreme track use. Power: 540 PS.
911 (MDA.BA, 2015–2019) — Be Careful: Premature water pump failure, Turbo oil return lines leaking, Piston and cylinder wall damage under extreme track use. Power: 581 PS.
911 (MA2.03, 2017–2019) — Be Careful: Water pump failure with internal coolant loss, Turbo oil feed pipe failure, Turbo shaft seal failure. Power: 450 PS.
911 (MDG.GA, 2017–2019) — Be Careful: Recall: defective connecting rods (718, 2021 batch), Lash cap detaches — oil pump blocks, Elevated oil consumption during track use. Power: 500 PS.
911 (MDH.NA, 2017–2019) — Stay Away!: Finger Follower Metallurgy Defect — High-Rev Operation, Connecting Rod Bolt Manufacturing Defect — Engine Failure, Intercooler Water Spray — Insufficient Tank Capacity. Power: 700 PS.
911 (MDG.GA, 2018–2019) — Be Careful: Recall: defective connecting rods (718, 2021 batch), Lash cap detaches — oil pump blocks, Elevated oil consumption during track use. Power: 520 PS.
What to watch out for with the Porsche 911? See the detailed listing of all engine and vehicle weaknesses in the sections above.
Frequently Asked Questions
What problems and weaknesses does the Porsche 911 991 have? +
What should I look for when buying a used Porsche 911 991? +
Which engine is recommended? +
Which Porsche 911 991 engine is the most reliable? +
Which Porsche 911 991 engine is the most fun? +
Is the Porsche 911 991 worth buying used? +
What horsepower variants are available for the Porsche 911 991? +
Last updated: February 2026 · All information without guarantee