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Porsche1997–2023 Critical issues documented

Porsche 911 991: common faults & what to check

The 991 is the Porsche 911 built 2011–2019. It was sold here with the 3.0 twin-turbo flat-6 and 3.8 twin-turbo (Turbo). Of the 18 faults documented for the 911, 5 apply to this generation, each with its symptoms, what to inspect and a typical repair cost. Free, no account needed.

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  • Odometer history
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  • NZ owned and operated

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18

Documented faults

Critical

Most serious

$1,500–$5,500

Typical repair

6

Systems covered

You're looking at the 991

2 engine variants are documented for this generation. Pick yours to narrow further, or keep reading for the generation as a whole.

Choose a different generation

Now narrow it to the engine

A 1.8 and a 2.4 of the same car do not fail the same way, so the faults below narrow to the engine as well as the year. Free, no account needed.

A 2013 Porsche 911 is the 991 generation (2011 to 2019).

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Porsche 911 991Engine not picked yet

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Can't confirm for this car

Porsche 911 · 2013

Narrowed to the year. No engine is recorded for this vehicle. Pick an engine to see which faults apply.

Tell us the engine, or check the engine code on the car, before relying on this.

  • No engine is recorded for this vehicle.

matched on year only

What to look out for

The checks worth doing on a Porsche 911 before you hand over any money. Every documented fault is listed below, each with its own page.

  • Costly issue

    Shine a torch through the front bumper intakes and look for packed leaves, bent fins and furry white corrosion on the cores.

    See why

    Front radiator/condenser corrosion and road-debris damage (991/992)

    The front-mounted radiators and air-conditioning condensers sit low in the nose intakes where leaves, road salt and stones collect; trapped debris rots the cores from the outside in. It is one of the most common out-of-warranty bills on modern 911s, and replacement means front bumper removal plus new cores and a re-gas. Mesh grille protection and periodic cleaning largely prevent it.

    What you would notice

    • Air-con losing performance or needing re-gassing
    • Coolant loss with no visible engine-bay leak
    • Visible debris or white corrosion in the front intakes

    Typically $2,000–$5,000 to put right.

  • Costly issue

    Review service history for walnut blasting intervals.

    See why

    Direct Injection Carbon Buildup on Intake Valves (991/992)

    The 991 and 992 generation 911s use MA1 and MA2 turbocharged flat-six engines with direct fuel injection only. DI does not wash intake valves with fuel, so oil vapour from the crankcase breather accumulates as hard carbon deposits on the back of the intake valves. Over time carbon restricts airflow, causes rough idle, misfires, and power loss. Walnut blasting (media blasting with walnut shell abrasive) through the intake ports is the accepted remedy, typically required every 50,000-80,000 km. A failed oil separator markedly accelerates buildup.

    What you would notice

    • Rough idle or hesitation on cold start
    • Misfires at low RPM or under light throttle
    • Gradual reduction in power or throttle response
    • Intake airflow or misfire fault codes in diagnostics

    Typically $800–$2,000 to put right.

  • Costly issue

    Cold-start the engine from fully cold and listen for chain rattle from the rear of the engine.

    See why

    MA1 Timing Chain Tensioner Failure on Cold Start (991.1)

    The 991.1 MA1 engine uses hydraulic timing chain tensioners dependent on oil pressure. On cold starts, particularly in cool ambient temperatures, oil pressure takes a moment to build and the tensioner cannot immediately maintain chain tension. This produces a brief rattle on startup and in severe or prolonged low-oil-pressure events can cause timing chain wear or tensioner failure. Documented on PCA and Rennlist forums. Porsche issued updated tensioner parts. The concern is most relevant on high-mileage 991.1 cars with degraded oil or infrequent oil changes.

    What you would notice

    • Brief chain rattle on cold start clearing within seconds of oil pressure build
    • Persistent timing chain rattle beyond initial startup warm-up phase
    • Check engine light with timing-related fault codes
    • Rough running after cold start that stabilises once warm

    Typically $2,000–$6,000 to put right.

  • Common issue

    Scan the car for stored cooling-system fault codes during the pre-purchase inspection and check coolant level against the marks.

    See why

    Cooling-circuit changeover/switching valve failures (991.1 9A1)

    The 991.1 uses several plastic vacuum-operated valves to manage the cooling circuit and intake flaps; the plastic housings crack with age and heat, throwing sporadic 'Cooling system fault' messages and sometimes causing slow coolant loss. Porsche fixed many under warranty in period, but out-of-warranty cars now pay for parts and diagnosis. It is a nuisance fault rather than an engine-killer if attended to promptly.

    What you would notice

    • Intermittent 'Cooling system fault' message on the dash
    • Slow unexplained coolant loss
    • Temperature gauge fluctuating

    Typically $500–$1,800 to put right.

See all 5 issues for this oneDocumented for the exact year and engine you picked.
Engine, transmission & cooling4

01MA1 Timing Chain Tensioner Failure on Cold Start (991.1)

Cold-start the engine from fully cold and listen for chain rattle from the rear of the engine.petrol2012–2016Engine
OccasionalEngine $2,000–$6,000 to fix

The 991.1 MA1 engine uses hydraulic timing chain tensioners dependent on oil pressure. On cold starts, particularly in cool ambient temperatures, oil pressure takes a moment to build and the tensioner cannot immediately maintain chain tension. This produces a brief rattle on startup and in severe or prolonged low-oil-pressure events can cause timing chain wear or tensioner failure. Documented on PCA and Rennlist forums. Porsche issued updated tensioner parts. The concern is most relevant on high-mileage 991.1 cars with degraded oil or infrequent oil changes.

The front of a dual overhead camshaft engine with the timing cover removed, exposing the timing chain and sprockets.Example of the part — not this vehicle

The front of a twin-cam engine with the timing cover off — chain, sprockets and guides.

Logansenf · CC BY-SA 4.0 · Wikimedia Commons

Symptoms to notice

  • Brief chain rattle on cold start clearing within seconds of oil pressure build
  • Persistent timing chain rattle beyond initial startup warm-up phase
  • Check engine light with timing-related fault codes
  • Rough running after cold start that stabilises once warm

What to check

Cold-start the engine from fully cold and listen for chain rattle from the rear of the engine. A single brief rattle clearing immediately is normal; rattle persisting at idle warrants tensioner and chain inspection. Verify oil level and condition — degraded oil worsens tensioner response time. Ask whether updated tensioner parts have been fitted by a Porsche specialist.

Where to look: Timing chain tensioners, rear of MA1 flat-six engine

Parts involved: Timing chain.

Ask the seller

  • “Has the timing chain tensioner been inspected or updated by a specialist?”
  • “Does the engine rattle on a fully cold start?”
  • “What oil specification and brand is used, and how frequently is it changed?”

02Front radiator/condenser corrosion and road-debris damage (991/992)

Shine a torch through the front bumper intakes and look for packed leaves, bent fins and furry white corrosion on the cores.petrol2012 onwardCooling
CommonCooling $2,000–$5,000 to fix

The front-mounted radiators and air-conditioning condensers sit low in the nose intakes where leaves, road salt and stones collect; trapped debris rots the cores from the outside in. It is one of the most common out-of-warranty bills on modern 911s, and replacement means front bumper removal plus new cores and a re-gas. Mesh grille protection and periodic cleaning largely prevent it.

Symptoms to notice

  • Air-con losing performance or needing re-gassing
  • Coolant loss with no visible engine-bay leak
  • Visible debris or white corrosion in the front intakes

What to check

Shine a torch through the front bumper intakes and look for packed leaves, bent fins and furry white corrosion on the cores. Ask whether mesh grilles were fitted and when the intakes were last cleaned out.

Where to look: Behind the three front bumper air intakes

Parts involved: Body corrosion, Radiator.

Ask the seller

  • “Have the radiators or A/C condensers ever been replaced?”
  • “Are protective mesh grilles fitted?”

03Direct Injection Carbon Buildup on Intake Valves (991/992)

Review service history for walnut blasting intervals.petrol2012 onwardEngineRead the full fault: symptoms, where to look, what to ask the seller

04Cooling-circuit changeover/switching valve failures (991.1 9A1)

Scan the car for stored cooling-system fault codes during the pre-purchase inspection and check coolant level against the marks.petrol2012–2016Cooling
CommonCooling $500–$1,800 to fix

The 991.1 uses several plastic vacuum-operated valves to manage the cooling circuit and intake flaps; the plastic housings crack with age and heat, throwing sporadic 'Cooling system fault' messages and sometimes causing slow coolant loss. Porsche fixed many under warranty in period, but out-of-warranty cars now pay for parts and diagnosis. It is a nuisance fault rather than an engine-killer if attended to promptly.

Symptoms to notice

  • Intermittent 'Cooling system fault' message on the dash
  • Slow unexplained coolant loss
  • Temperature gauge fluctuating

What to check

  1. Scan the car for stored cooling-system fault codes during the pre-purchase inspection and check coolant level against the marks.
  2. Ask for records of any warranty valve replacements.

Where to look: Coolant circuit valves around the engine bay and underbody coolant lines

Ask the seller

  • “Has the car ever shown a cooling system fault message?”
  • “Were the switching/changeover valves replaced under warranty?”
Depends on the exact engine — 1 moreDocumented for a specific engine we could not confirm from what you picked. Check the engine code on the car.
Engine, transmission & cooling1

01PDK Dual-Clutch Solenoid and Mechatronic Wear

Check PDK fluid service history — if not changed within 60,000 km or 4 years it is overdue.petrol2009 onwardTransmission
OccasionalTransmission $2,500–$8,000 to fix

Can't confirm for this car

The 7-speed PDK fitted to 997.2 onwards is generally robust but develops solenoid wear and mechatronic unit faults with age and high mileage. Worn solenoids cause incorrect gear engagement, harsh downshifts, or refusal to engage a specific ratio. Porsche specifies PDK fluid changes every 4 years or 60,000 km, but many cars arrive at workshops with original fluid at far higher mileage, accelerating internal wear. Mechatronic unit replacement is the most common major repair.

Symptoms to notice

  • Harsh or jerky gear changes especially during low-speed downshifts
  • A specific gear ratio refusing to engage or slipping unexpectedly
  • Transmission warning light or fault codes on the instrument cluster
  • Delayed engagement from park or neutral on startup

What to check

Check PDK fluid service history — if not changed within 60,000 km or 4 years it is overdue. During the test drive, cycle through all gears in manual mode and note any harsh or hesitant shifts. Connect Durametric or PIWIS to read PDK-specific fault codes before purchase. A specialist PDK fluid change and solenoid adaptation may resolve early-stage faults.

Where to look: PDK gearbox mechatronic unit and solenoids, internal to transmission housing

Parts involved: Mechatronic / valve body, Clutch.

Ask the seller

  • “When was the PDK fluid last changed, and was it done by a Porsche specialist?”
  • “Are there any harsh shifts or hesitations when changing gears?”
  • “Has the PDK ever triggered a fault code or warning light?”
Other Porsche 911 engines and years13 documented issues that do not apply to the one you picked.
Engine, transmission & cooling9

01IMS bearing failure (996/997.1 M96/M97 flat-6)

Ask for the invoice for an IMS retrofit (LN Engineering ceramic or equivalent) and check the oil filter cutting report from the last service.petrol2000–2008Engine
OccasionalEngine $4,000–$45,000 to fix

Does not apply

The sealed intermediate shaft (IMS) bearing that drives the camshafts has no oil feed; its grease breaks down and the bearing can disintegrate, throwing the cam timing and destroying the engine. Single-row bearings fitted roughly 2001-2005 are the worst (about 8% failure claimed in the US Eisen class action), dual-row pre-2001 cars around 1%, and the larger non-serviceable bearing in 2006-2008 997.1s fails rarely but cannot be retrofitted without splitting the engine. 997.2 (2009-on), GT3 and Turbo models use a different design and are not affected. A documented ceramic/roller retrofit done with a clutch job largely removes the risk; an actual failure means a full engine rebuild or replacement.

Symptoms to notice

  • Metallic rattle or knocking from the rear of the engine at idle
  • Glitter-like metal debris in the oil filter
  • Oil leak at the engine/gearbox join
  • Sudden loss of cam timing / engine stops (end stage)

What to check

Ask for the invoice for an IMS retrofit (LN Engineering ceramic or equivalent) and check the oil filter cutting report from the last service. On a pre-purchase inspection have the filter cut open and the sump plug checked for metal. If no retrofit has been done on a 2001-2005 car, price one into your offer.

Where to look: Rear of the engine where it meets the gearbox (flywheel end), only visible with the transmission removed

Parts involved: Clutch, Turbocharger.

Ask the seller

  • “Has the IMS bearing been replaced or retrofitted, and is there an invoice?”
  • “Which bearing type does this car have (dual-row, single-row, or large non-serviceable)?”
  • “Was the oil filter inspected for metal at the last service?”

02Cylinder bore scoring (996/997.1 M96/M97, worst on 3.8)

Start the car stone cold and listen at the rear for ticking.petrol2000–2008Engine
OccasionalEngine $20,000–$45,000 to fix

Does not apply

The Lokasil cylinder walls in the M96/M97 engine can score vertically, especially bank 2 (cylinders 4-6) which runs hotter, and the 3.8-litre 997.1 Carrera S is the highest-risk variant. Scoring starts as a cold-start tick and progresses to heavy oil use, soot and ultimately a seized piston; the only proper fix is a rebuild with new liners or a replacement engine. UK specialists Hartech and US specialist Flat 6 Innovations have documented the failure mode extensively. 997.2 cars (2009-on) with the 9A1 direct-injection engine are largely free of the problem.

Symptoms to notice

  • Ticking/tapping from the engine when cold that fades as it warms
  • Left-side (bank 2) exhaust tip noticeably sootier than the right
  • Rising oil consumption
  • Aluminium glitter in the oil filter

What to check

  1. Start the car stone cold and listen at the rear for ticking.
  2. Compare soot on the two exhaust tips - a sooty bank 2 tip is a classic tell.
  3. Insist on a borescope inspection of the bores as part of the pre-purchase inspection; it costs a few hundred dollars against a $30,000+ downside.

Where to look: Cylinder walls inside the engine, bank 2 (left side facing forward) most affected; evidence at exhaust tips and oil filter

Ask the seller

  • “Has this engine ever been borescoped, and can I see the images?”
  • “How much oil does it use per 1,000 km?”
  • “Has the engine ever been rebuilt or replaced?”

03M97 Cylinder Bore Scoring (997 3.8 S / Early DFI Engines)

Request a full compression and leakdown test on all six cylinders.petrol2005–2008Engine
OccasionalEngine $14,000–$35,000 to fix

Does not apply

The 997 Carrera S and 4S models with the 3.8-litre M97/76 engine suffered bore scoring — cylinder wall damage from insufficient lubrication caused by direct fuel injection washing the bore walls during cold-start enrichment. Scored bores cause progressive oil consumption, reduced compression, and ultimately require engine rebuild or replacement. Jake Raby and Flat Six Innovations documented this extensively across 997 production. Most prevalent in 3.8 S variants but also found in some 3.6 engines.

Symptoms to notice

  • High oil consumption exceeding 1 litre per 1,000 km
  • Blue smoke from exhaust on overrun or cold start
  • Loss of compression on one or more cylinders
  • Gradual reduction in power and throttle response

What to check

Request a full compression and leakdown test on all six cylinders. Review service history for oil top-up frequency — consumption above 1 litre per 1,000 km warrants bore scope inspection. A pre-purchase bore scope by a Porsche specialist is the definitive test. Cold-start the engine and observe the exhaust for blue smoke on the overrun.

Where to look: Cylinder bores of the flat-six engine, most commonly cylinders 1, 2, and 3

Ask the seller

  • “What is the oil consumption rate between services?”
  • “Has a bore scope or leakdown test been performed recently?”
  • “Has the engine been rebuilt or had cylinders sleeved?”

04M96/M97 Intermediate Shaft (IMS) Bearing Failure

Confirm whether LN Engineering IMS retrofit or factory dual-row bearing upgrade has been fitted — require workshop receipt.petrol1997–2008Engine
CommonEngine $8,000–$28,000 to fix

Does not apply

The M96 and M97 flat-six engines fitted to 996 and 997 generation 911s use a single-row (M96) or dual-row (M97) intermediate shaft bearing pressed into the rear main housing. The bearing is lightly loaded but subject to marginal lubrication at low-rev oil pressure. Failure is typically catastrophic and without warning — the bearing collapses, the intermediate shaft sheds, and debris destroys the engine internals. LN Engineering documented failure rates above 10% in field studies. Porsche faced class-action litigation in the USA and Australia over this design. Preventive replacement with an LN Engineering IMS Pro bearing or complete engine-out rebuild is strongly advised on pre-purchase. The 997.2 Carrera from 2009 uses the 9A1 engine with no IMS bearing, and Turbo, GT2 and GT3 models use the Mezger engine, which never had this bearing. The 997.2 Carrera from 2009 uses the 9A1 engine with no IMS bearing, and Turbo, GT2 and GT3 models use the Mezger engine, which never had this bearing. The 997.2 Carrera from 2009 uses the 9A1 engine with no IMS bearing, and Turbo, GT2 and GT3 models use the Mezger engine, which never had this bearing. The 997.2 Carrera from 2009 uses the 9A1 engine with no IMS bearing, and Turbo, GT2 and GT3 models use the Mezger engine, which never had this bearing. The 997.2 Carrera from 2009 uses the 9A1 engine with no IMS bearing, and Turbo, GT2 and GT3 models use the Mezger engine, which never had this bearing. The 997.2 Carrera from 2009 uses the 9A1 engine with no IMS bearing, and Turbo, GT2 and GT3 models use the Mezger engine, which never had this bearing.

Symptoms to notice

  • Sudden catastrophic engine noise followed by immediate loss of power
  • Metal particles visible in engine oil at service
  • Oil pressure warning light triggered at low idle
  • Rattling from rear of engine at cold start (advanced bearing wear)

What to check

  1. Confirm whether LN Engineering IMS retrofit or factory dual-row bearing upgrade has been fitted — require workshop receipt.
  2. Check engine oil on dipstick for metallic particles or gritty texture.
  3. Review service history for proactive bearing replacement evidence.
  4. Early 996 (1997-2001) carries higher risk due to the single-row bearing design.
  5. Cold-start the engine and listen for bearing rattle from the centre-rear of the engine.

Where to look: Rear of engine, intermediate shaft bearing housing between the two cylinder banks

Parts involved: Turbocharger.

Ask the seller

  • “Has the IMS bearing been replaced or retrofitted by a Porsche specialist?”
  • “Can you provide the workshop invoice for the bearing work?”
  • “When was the last oil change and was a magnetic drain plug used?”

05M96 Cylinder Head Bolt Pull-Out (Early 996)

Confirm build date and whether the car is a pre-MY2002 model.petrol1997–2001Engine
OccasionalEngine $4,000–$10,000 to fix

Does not apply

Early production M96 engines in 996 models built 1997-2001 used a head bolt pattern carried over from the air-cooled 993. The bolt torque specification and thread engagement depth were insufficient for the water-cooled M96 under thermal cycling at load. Bolts can pull out of the aluminium block, causing head gasket failure, coolant ingestion, and overheating. Most surviving early 996s will have had this addressed, but unverified cars need investigation. Later M96 production revised the bolt specification.

A removed six-cylinder diesel engine cylinder head on cardboard, valve-gear side facing up.Example of the part — not this vehicle

A six-cylinder diesel head off the engine, valve-gear side up. Cracks run between the valve seats on the face beneath.

Ll1324 · CC0 · Wikimedia Commons

Symptoms to notice

  • Coolant loss with no visible external leak
  • White smoke from exhaust consistent with coolant combustion
  • Engine overheating under load or at highway speed
  • Milky emulsion on underside of oil filler cap

What to check

  1. Confirm build date and whether the car is a pre-MY2002 model.
  2. Ask whether head bolts have been replaced or upgraded.
  3. Check for coolant consumption without any external leak.
  4. Inspect the oil filler cap underside for white creamy emulsion.
  5. Carry out a coolant combustion test using a CO2 sniffer at the radiator header tank during a warm test drive.

Where to look: Cylinder head-to-block bolts on both cylinder banks of the flat-six

Parts involved: Cylinder head.

Ask the seller

  • “Has the car had a head bolt inspection or upgrade by a Porsche specialist?”
  • “Has it ever overheated or had a head gasket failure?”
  • “Is there any history of coolant loss or white exhaust smoke?”

06Water pump and coolant line leak at pump housing (991.2 3.0 turbo)

Have the workshop pressure-test the cooling system and inspect the pump housing joint for staining during the pre-purchase inspection.petrol2016–2019Cooling
OccasionalCooling $1,500–$3,200 to fix

Does not apply

On 991.2 Carreras, particularly 2017-2018 model years, the plastic coolant line where it meets the water pump housing is a known failure point that weeps and then leaks coolant. Porsche extended the warranty on the water pump and valve block to 10 years in North America, which signals how widespread it was; NZ/AU cars carry no such extension so buyers wear the cost. Caught early it is a straightforward pump/line replacement; ignored it risks overheating the engine.

Symptoms to notice

  • Coolant smell after a run
  • Low coolant warning
  • Dried coolant residue around the water pump area
  • Overheating in traffic if far gone

What to check

Have the workshop pressure-test the cooling system and inspect the pump housing joint for staining during the pre-purchase inspection. Check invoices for a water pump replacement - on a 2017-2018 car treat an original pump as a near-term service item.

Where to look: Water pump on the engine, accessed from under the rear of the car

Parts involved: Water pump, Turbocharger.

Ask the seller

  • “Has the water pump or its coolant line ever been replaced?”
  • “Has the car ever lost coolant or overheated?”

07Air-oil separator (AOS) failure (M96/M97)

Cold-start the car and watch the exhaust for smoke that clears after a minute.petrol2000–2008Engine
CommonEngine $900–$1,800 to fix

Does not apply

The plastic air-oil separator that scavenges oil mist from crankcase vapours fails with age, letting the engine pull oil into the intake. A failed AOS produces a spectacular cloud of white-blue smoke, usually on start-up, and can foul plugs and catalytic converters; in bad cases the engine can hydro-lock on oil. It is a service item on these cars and moderately labour-intensive to reach.

Symptoms to notice

  • Large puff or cloud of white-blue smoke on start-up
  • High vacuum on the oil filler cap at idle
  • Rough idle and oil-fouled spark plugs
  • Whistling noise from the engine bay

What to check

Cold-start the car and watch the exhaust for smoke that clears after a minute. With the engine idling, carefully open the oil filler cap - excessive suction suggests a failing AOS diaphragm.

Where to look: Upper left-forward side of the engine, engine bay

Parts involved: PCV / oil separator.

Ask the seller

  • “Has the air-oil separator been replaced, and when?”
  • “Does it ever smoke on start-up?”

08Coolant expansion tank cracking and leaking caps (996/997)

Check the coolant level and look for dried pink/white residue around the tank (right side of the engine bay) and beneath the car.petrol2000–2012CoolingRead the full fault: symptoms, where to look, what to ask the seller

09Ignition coil cracking and misfires (992 MA2 3.0/3.8)

Scan for misfire codes during the pre-purchase inspection and ask whether the coils are the latest revision.petrol2019 onwardEngine
CommonEngine $800–$1,800 to fix

Does not apply

The original ignition coils on the 992's MA2 twin-turbo flat-6 were prone to cracking, causing misfires; Porsche has revised the coil design multiple times. A rough idle or misfire count under load on an early 992 is very often coils rather than anything sinister, and many cars had them replaced under warranty. Out of warranty, a full set of six with labour is a moderate bill at an independent Porsche specialist.

A four-cylinder ignition coil rail removed from an engine, beside a steel rule for scale.Example of the part — not this vehicle

A coil-on-plug ignition rail, removed. One coil per cylinder.

Cschirp · CC BY-SA 3.0 de · Wikimedia Commons

Symptoms to notice

  • Misfire or stumble under load
  • Rough idle
  • Check-engine light with misfire codes
  • Slight hesitation on cold start

What to check

  1. Scan for misfire codes during the pre-purchase inspection and ask whether the coils are the latest revision.
  2. Test drive with firm acceleration and feel for stumbles.

Where to look: Ignition coils on top of each cylinder bank, rear engine bay

Parts involved: Ignition coil.

Ask the seller

  • “Have the ignition coils been updated to the latest revision?”
  • “Has the car ever had misfire faults logged?”
Body, brakes, suspension & interior3

01PASM Active Damper Actuator Failure (997)

Confirm the PASM button toggles between Normal and Sport modes and that a change in ride firmness is felt.petrol2005–2012SuspensionRead the full fault: symptoms, where to look, what to ask the seller

02Front-axle lift system faults — 'Lift system fault — service necessary' warning (992)

First check whether the car actually has the front-lift option (button/menu near the suspension controls).petrol2019 onwardSuspension
OccasionalSuspension $400–$7,000 to fix

Does not apply

On 992s fitted with the optional hydraulic front-axle lift, owners report the white 'Lift system fault — service necessary' warning appearing and the lift refusing to work. Porsche's own Technical Information 40/21 (ENU 4381) covers the fault: the system logs a vehicle-height measuring fault (code 000302) and it can be triggered simply by parking the car with the nose raised, which Porsche says not to do because the raised position cannot be held long-term with the engine off. Many cases clear with a ride-height recalibration, but genuine hydraulic pump, sensor or line failures out of warranty are expensive. On a car with the lift option, the system's behaviour is worth five minutes of the viewing.

Symptoms to notice

  • 'Lift system fault — service necessary' message in the instrument cluster
  • Front lift refuses to raise or lower
  • Nose slowly settles after being parked raised
  • Lift works but throws an error when lowering

What to check

First check whether the car actually has the front-lift option (button/menu near the suspension controls). During the viewing, raise and lower the nose several times from cold and again after the test drive — each cycle should complete within seconds with no warning message. Ask the owner whether they ever park it with the nose raised (Porsche's guidance is not to) and whether the lift has ever shown a fault or been recalibrated. Look under the front bumper lip for any hydraulic weep around the lift struts after the car has been sitting. If a workshop inspection is possible: read the front-axle lift control unit's fault memory for stored height-measurement fault 000302 and other codes, and inspect the lift hydraulic pump and lines for seepage per Porsche Technical Information 40/21 ENU 4381.

Where to look: Hydraulic lift units on the front suspension struts with the pump in the front of the car; fault appears as a message in the instrument cluster

Ask the seller

  • “Has the lift system ever shown a fault or needed recalibration?”
  • “Do you park the car with the front raised?”
  • “Was any lift work done under warranty, and is there an invoice?”

03Windscreen seal 'melting trim': adhesive reaction turns the glass surround sticky (992)

petrol2020–2023Body & Rust
OccasionalBody & Rust $2,500–$5,500 to fix

Does not apply

Porsche's Advanced Technical Information bulletin 2401.3 documents windscreen (and rear window) seals on 992s built between 2020 and 2023 turning soft, sticky and 'melted'-looking. The cause is a chemical incompatibility between the seal material and the glass bonding adhesive; sunlight and heat make it worse, so it shows up earliest on cars that live outside. The trade nicknames it Melting Trim Syndrome, and it affects several Porsche models of this era. It is cosmetic rather than dangerous, but the proper fix under the bulletin is a replacement windscreen with revised seal materials — real money once out of warranty — so check it and use it in negotiation.

Symptoms to notice

  • Black windscreen surround looks wet, oozy or smeared
  • Sticky residue on the glass edge or paint beside the trim
  • Seal appears dissolved or sagging at the top corners
  • Same appearance starting on the rear window seal

What to check

In good light, walk around the glass: look closely at the black seal around the windscreen and rear window, especially the top edge and corners, for a wet-looking, oozing or smeared finish, and glance at the paint alongside for sticky streaks. Touch the seal lightly with a knuckle — it should feel dry and rubbery, not tacky. Cars parked outdoors in sun show it worst, so ask where the car lives. Ask whether the windscreen or rear glass has been replaced under Porsche's seal bulletin and for the invoice, since replacement glass uses revised materials. If a workshop inspection is possible: have a glass specialist or dealer confirm whether the VIN has had the bulletin 2401-series windscreen seal repair performed.

Where to look: Black bonded seal around the edge of the windscreen and rear window

Ask the seller

  • “Has the windscreen or rear window ever been replaced under Porsche's seal bulletin?”
  • “Is the car garaged or parked outside in the sun?”
  • “Is there any stickiness or smearing on the glass surrounds now?”
Fluid leaks1

01M96/M97 Rear Main Seal Oil Leak

Inspect the bell housing mating face and underside of the engine with a torch.petrol1997–2008Fluid LeaksRead the full fault: symptoms, where to look, what to ask the seller

Porsche 911 faults in detail

Narrowed to the Porsche 911 · 2013. Each of these has its own page: the symptoms, where to look, what to ask the seller and what the repair costs. Free, no account needed.

Direct Injection Carbon Buildup on Intake Valves (991/992)Major · Engine

What these repairs cost on other cars

Some of the Porsche 911’s documented faults are repairs other models share. Each page lists the documented NZ cost for every model it affects.

Other Porsche models

Porsche Cayenne23 documented faultsPorsche Boxster/Cayman9 documented faultsPorsche Macan6 documented faults

Porsche 911 buyer questions

Is the Porsche 911 reliable?

Like any used car, it depends on the specific example and its service history. Across the 18 documented faults for the Porsche 911, the recurring problem areas are engine, transmission, and suspension. A Porsche 911 with a full service history and no signs of the issues listed on this page can be a sound buy but each one needs to be checked individually before you commit.

What are the most common problems with a used Porsche 911?

We've catalogued 18 known faults for the Porsche 911, covering engine, transmission, and suspension. All 18 are written out in full on this page, with the symptoms to notice, what to inspect, and typical repair costs for each. Free to read, no account needed.

How much do repairs cost on a Porsche 911?

Most single repairs on the Porsche 911 fall between $1,500–$5,500 at NZ independent-workshop rates. Some of the 18 documented faults cost less and a few cost considerably more, and no one car needs them all. Knowing which ones to look for before you view is what lets you negotiate the price down or walk away.

Should I get a pre-purchase inspection on a Porsche 911?

Yes. A Porsche 911 inspection focused on its known weak points is the single best way to avoid an expensive mistake. KickTyres gives you a guided, model-specific inspection plus a market valuation and negotiation figure for $24.90 far less than the cost of missing one of the faults on this page.