According to Au7o's analysis of 12,100+ owner reports, the 2001 Porsche 911 has 3 documented known issues, with 1 rated critical. The most serious is Intermediate Shaft (IMS) Bearing Failure ($2,000-$4,500 repair). The most commonly reported issue is Intermediate Shaft (IMS) Bearing Failure with 5,500 owner reports. Across all issues with published estimates, repair costs range from $500 to $4,500. DIY maintenance guides at au7o.io.
On the 1999-2008 Porsche 911, the IMS bearing on 996 and early 997 flat-six engines is a single-row or dual-row sealed bearing that loses lubrication over time, leading to catastrophic bearing failure and engine destruction. The dual-row bearing (1999-2005) fails less frequently than the single-row (2006-2008), but both are a major concern. This is the most feared and well-documented Porsche defect of the modern era.
Replace the IMS bearing with an upgraded ceramic hybrid bearing (LN Engineering IMS Solution or IMS Retrofit). This can be done with the engine in the car during a clutch replacement. On 2006-2008 single-row cars, replacement is strongly recommended as a preventive measure.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
1999 Porsche 996 911 and confirmed dual-row 2000-2001 M96 engines; SKU 106-08.40. Identify the actual bearing/engine first, prequalify it and use a qualified Porsche specialist.
Confirmed single-row 2000-2005 Porsche 996/early 997 M96 or early M97 engines, SKU 106-08.20. Excludes late non-serviceable 2005 engines and all 2006-2008 large-bearing engines unless the engine is completely disassembled.
High Confidence5,500 owner reportsLast reported by owners Jan 2026Reviewed Mar 2026
Community reported
3,800 owners
On the 1999-2019 Porsche 911, the rear main seal on the M96, M97, and MA1 flat-six engines is prone to leaking oil onto the clutch and flywheel. The seal hardens over time and the flange design allows oil to migrate past the seal. This is often discovered during clutch replacement or when oil drips appear under the rear of the car.
Replace the rear main seal. This requires transmission removal and is commonly done alongside clutch replacement and IMS bearing upgrade to save labor costs. Use the updated Porsche OEM seal design.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
Genuine Porsche 0PB105249 updated PTFE rear main seal
1999-2008 Porsche 911 996/997 M96/M97 applications after VIN/engine confirmation; 0PB105249 supersedes 99710121200 and 99911349040. Excludes 2009-2019 MA1 engines.
High Confidence3,800 owner reportsLast reported by owners Dec 2025Reviewed Mar 2026
Community reported
2,800 owners
On the 1999-2008 Porsche 911, the AOS diaphragm on M96/M97 engines ruptures over time, causing unmetered air leaks into the intake manifold and excessive oil consumption. The failed AOS allows oil vapor to be drawn directly into the intake system rather than being separated and returned to the crankcase. This leads to rich running, fouled spark plugs, and smoke from the exhaust.
Replace the AOS unit. Use an updated OEM Porsche unit or aftermarket upgrade from LN Engineering. The AOS is located in the engine V between the cylinder banks and requires moderate disassembly to access.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
Genuine Porsche 99610702355 air-oil separator
Confirm hose/clamp requirements and exclude Turbo/GT models.
2005-2008 Porsche 997 Carrera S, 2006-2008 Carrera 4S and applicable 2007-2008 Targa 4S 3.8L; 99710703801 supersedes 99710703800. Not the separate secondary separator.
High Confidence2,800 owner reportsLast reported by owners Nov 2025Reviewed Mar 2026
NHTSA Recalls7 recalls
SUSPENSION:REAR
Porsche Cars North America, Inc. (Porsche) is recalling certain 2019 Porsche 911 Speedster, 2020 Porsche 911 Carrera S Coupe, Carrera 4S Coupe, and Carrera S Cabriolet vehicles. The screw connection on the rear axle upper control arm may be loose.
Campaign #21V20100024/03/2021
AIR BAGS: AIR BAG/RESTRAINT CONTROL MODULE
Porsche Cars North America, Inc. (Porsche) is recalling certain 2016-2017 911 and Boxster, 2016 Cayman and Panamera vehicles. The air bag Electronic Control Unit (ECU) may have a defective power supply capacitor that can result in air bag deactivation or inadvertent deployment of the air bags.
Campaign #19V53300017/07/2019
AIR BAGS:SIDE/WINDOW
Porsche Cars North America, Inc. (Porsche) is recalling certain model year 2017 718 Boxster, 718 Boxster S, 718 Cayman, 718 Cayman S, 911 Carrera, 911 Carrera S, 911 Carrera S Cabriolet, 911 Carrera 4S, 911 Turbo, 911 Turbo S, 911 Carrera 4S Cabriolet, and 911 Turbo Cabriolet vehicles. The seat mounted side air bag inflator initiator may fail to ignite during a crash.
Campaign #16V94600030/12/2016
AIR BAGS
Porsche Cars North America, Inc. (Porsche) is recalling certain 2018 718 Boxster, Boxster S and Boxster GTS, 718 Cayman, Cayman S and Cayman GTS, 911 Carrera, Carrera T, Targa 4 GTS, Carrera 4, Carrera S, Carrera 4S, Carrera GTS, Carrera 4 GTS, Carrera Cabriolet, Carrera S Cabriolet, Carrera 4S Cabriolet, Carrera GTS Cabriolet, Carrera 4 GTS Cabriolet, Targa 4, Targa 4S, Turbo, Turbo S, Turbo S Exclusive Series, Turbo Cabriolet, Turbo S Cabriolet and GT3 vehicles. The side air bag impact sensors may not have been properly tightened to the vehicle.
Campaign #19V17900006/03/2019
VISIBILITY:WINDSHIELD
Porsche Cars North America, Inc. (Porsche) is recalling certain 2017 911 Carrera Cabriolet, 911 Carrera 4 Cabriolet, 911 Carrera 4S Cabriolet, 911 Carrera S Cabriolet, 911 Targa S, 911 Targa 4S, 911 Turbo Cabriolet, 718 Boxter and 718 Boxter S vehicles. During manufacturing, the windshield may not have been properly bonded to the vehicle, allowing it to detach in a crash. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 212, "Windshield Mounting."
According to Au7o's analysis of 12,100+ owner reports, the 2001 Porsche 911 has 3 documented issues. The most frequently reported are: Intermediate Shaft (IMS) Bearing Failure, Rear Main Seal (RMS) Oil Leak, Air-Oil Separator (AOS) Failure. Of these, 1 is rated critical and should be addressed promptly.
Is the Porsche 911 reliable?
The 2001 Porsche 911 has 3 known issues documented across 12,100+ owner reports. 1 issue is rated critical: Intermediate Shaft (IMS) Bearing Failure. Prospective buyers should inspect for these issues and factor potential repair costs into their purchase decision. Regular maintenance following the manufacturer's schedule helps prevent many common problems.
How much does it cost to fix common Porsche 911 problems?
Repair costs for known Porsche 911 issues range from $500 to $4,500, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, Intermediate Shaft (IMS) Bearing Failure, typically costs $2,000-$4,500 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.
What is the 1999-2008 Porsche 911 Intermediate Shaft (IMS) Bearing Failure?
The IMS bearing on 996 and early 997 flat-six engines is a single-row or dual-row sealed bearing that loses lubrication over time, leading to catastrophic bearing failure and engine destruction. The dual-row bearing (1999-2005) fails less frequently than the single-row (2006-2008… Repairs typically run $2,000-$4,500. Severity: high.
What is the 1999-2019 Porsche 911 Rear Main Seal (RMS) Oil Leak?
The rear main seal on the M96, M97, and MA1 flat-six engines is prone to leaking oil onto the clutch and flywheel. The seal hardens over time and the flange design allows oil to migrate past the seal. This is often discovered during clutch replacement or when oil drips appear und… Repairs typically run $1,500-$3,500. Severity: medium.
What is the 1999-2008 Porsche 911 Air-Oil Separator (AOS) Failure?
The AOS diaphragm on M96/M97 engines ruptures over time, causing unmetered air leaks into the intake manifold and excessive oil consumption. The failed AOS allows oil vapor to be drawn directly into the intake system rather than being separated and returned to the crankcase. This… Repairs typically run $500-$1,500. Severity: medium.
Content on this page was compiled with AI assistance using NHTSA complaints, TSBs, owner reports, and public automotive data. While we strive for accuracy, this information may contain errors. Always verify repair procedures and specifications with your vehicle's service manual or a qualified mechanic.
