Porsche 911 997: common faults & what to check

You're looking at the 997

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

2004–2012997 Selected2004–20129973.6 flat-6 petrolPetrolDocumented issues6 knownSee faults & what to checkPhoto: The Car Spy via Wikimedia Commons, CC BY 2.0.

2004–2012997 Selected2004–20129973.8 flat-6 petrolPetrolDocumented issues8 knownSee faults & what to checkPhoto: The Car Spy via Wikimedia Commons, CC BY 2.0.

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.

Start your free check on this Porsche 911

No plate needed. You get the risk score, the buyer's checklist and the guided inspection for the exact car you picked above — not the whole nameplate.

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.

• Serious issue

  Confirm whether LN Engineering IMS retrofit or factory dual-row bearing upgrade has been fitted — require workshop receipt.

  See why

  M96/M97 Intermediate Shaft (IMS) Bearing Failure

  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.

  What you would 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)

  Typically $8,000–$28,000 to put right.

• Serious issue

  Ask for the invoice for an IMS retrofit (LN Engineering ceramic or equivalent) and check the oil filter cutting report from the last service.

  See why

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

  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.

  What you would 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)

  Typically $4,000–$45,000 to put right.

• Costly issue

  Confirm the PASM button toggles between Normal and Sport modes and that a change in ride firmness is felt.

  See why

  PASM Active Damper Actuator Failure (997)

  Porsche Active Suspension Management (PASM) uses electronically controlled dampers that adjust stiffness in real time. The solenoid actuators inside each strut are a documented failure point on 997 models, particularly in NZ/AU operating conditions. Failure triggers a PASM warning light and defaults the suspension to a fixed damping state. Individual strut replacement is the only repair — OEM units are expensive, though aftermarket PASM-compatible alternatives exist. High-mileage 997s over 10 years old commonly present with at least one failed actuator.

  What you would notice

  • PASM warning light on instrument cluster
  • Suspension stuck in firm or soft mode regardless of switch position
  • Uneven ride quality between corners
  • PASM fault codes in Porsche PIWIS or Durametric diagnostics

  Typically $1,500–$5,500 to put right.

• Costly issue

  Inspect the bell housing mating face and underside of the engine with a torch.

  See why

  M96/M97 Rear Main Seal Oil Leak

  The M96 and early M97 flat-six engines are known for rear main seal oil leakage, a consequence of the engine's hollow intermediate shaft design which creates internal pressure variation. The rear main seal sits between the engine and transaxle and requires engine extraction to replace. Leaks typically pool on the underside of the bell housing and drip onto the exhaust, causing a burning oil smell. Not immediately catastrophic but a strong negotiation point and signal that engine-out work is imminent.

  What you would notice

  • Oil drip or film on underside of bell housing and rear of engine
  • Burning oil smell from exhaust area after driving
  • Oil spots on garage floor beneath the rear centre of the car
  • Unexplained low oil level between services

  Typically $1,200–$3,200 to put right.

• Costly issue

  Cold-start the car and watch the exhaust for smoke that clears after a minute.

  See why

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

  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.

  What you would 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

  Typically $900–$1,800 to put right.

• Costly issue

  Check the coolant level and look for dried pink/white residue around the tank (right side of the engine bay) and beneath the car.

  See why

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

  The plastic coolant expansion tank in the engine bay hardens with heat cycles and cracks along its lower seams, dumping coolant onto the engine and road. It affects every water-cooled 996 and 997 including Turbo and GT models. Early blue coolant caps also leaked and were superseded; an old cap lets coolant dribble down the overflow onto the exhaust. Cheap part, awkward labour because the tank is buried in the engine compartment.

  What you would notice

  • Sweet coolant smell from the engine bay after a drive
  • Low coolant warnings
  • White crusty residue or damp patch below the right-rear of the engine bay
  • Steam from the rear on hot days

  Typically $700–$1,600 to put right.

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.

• Timing Chain Replacement Cost
• DSG and Dual-Clutch Gearbox Repair Cost

Other Porsche models