The 2005 model year Porsche 911 Carrera, part of the 997 generation, is a sought-after sports car. However, like many models from this era, it’s essential for potential owners and enthusiasts to be aware of specific mechanical considerations. One significant topic for the 2005 Porsche 911 Carrera is the Intermediate Shaft (IMS) bearing. This component, while crucial to engine function, has been a point of discussion regarding reliability in certain Porsche models.
It’s important to clarify that the 2005 911 Carrera, equipped with the M96 engine, utilizes a single row IMS bearing. This is a distinction from earlier M96 engines found in models like the 986 Boxster and 996 generation 911, which featured a double row bearing. Interestingly, early Boxsters with the double row bearings are often perceived as having fewer IMS issues compared to later single row versions in some models. Porsche has indeed revised the IMS bearing and seal design multiple times, as noted by sources like LN Engineering, indicating ongoing efforts to address potential weaknesses.
While the single row IMS bearing in the 2005 911 Carrera is often considered more robust than its double row predecessor, it’s not immune to failure. Although data suggests that IMS failures became less frequent after 2007, particularly with the introduction of the M97 engine in the Boxster and Cayman, issues can still occur in cars like the 2005 911 Carrera. Notably, the 3.8 liter ‘S’ model 911, which shares a similar M97 engine designation with the Cayman and Boxster 3.4, also seems to exhibit fewer IMS bearing problems. The early Boxster 987 and 3.6 liter engines in the 911 (997), alongside previous 911 generations (996) all share the M96 engine variant, placing them within the scope of IMS bearing discussions.
The exact reasons for IMS bearing failure are still debated. Theories range from inadequate bearing lubrication due to low viscosity oil, to contamination from sludge and acidity, especially in vehicles used for short trips or with extended oil change intervals. Manufacturing tolerances or assembly faults are also considered potential contributing factors. Furthermore, the IMS shaft support itself can be vulnerable, particularly at the thread end on the spigot. Porsche addressed this concern in 2006 by introducing a larger spigot and revised bearing, aiming to improve the system’s durability.
When considering a Porsche 911 from this era, such as a 997 or even a 996, concerns about IMS failure should be weighed carefully. The risk level might be comparable between these generations. However, later models produced after 2006, benefiting from the larger spigot and revised bearing, are statistically less likely to suffer IMS issues. Experience with the Cayman and Boxster models suggests that these modifications did contribute to reducing IMS bearing and shaft failures, although the IMS seal issue might still persist.
Regardless of the specific 2005 Porsche 911 Carrera model or production date, and even for post-2006 cars, acquiring a comprehensive warranty is a prudent step. Porsche parts and labor costs are substantial. The increasing complexity of modern vehicles means there are more components that could potentially require repair. For example, replacing rear suspension arms can cost around £600 in the UK, while radiators can range from £300 to £400, with other parts being similarly priced. It’s not uncommon to face repair bills exceeding £1000 (or $1500 USD), even when using independent mechanics and avoiding main dealer rates. Therefore, for peace of mind and financial protection, especially when considering a 2005 Porsche 911 Carrera, a warranty remains a valuable investment.
