"996" 911 Maintenance & Repair Articles
1999 - 2001 (996.1 series)
2002 - 2004 (996.2 series)

The Porsche “996” generation of 911 is credited for saving the 911 while showing us that the rear-engined layout 911 had plenty more development left, ensuring it’s place at the top of the sports car market for years to come.   (See our 996.1 Article below for more 996 history and specifics related to the 996.1).

The 996.2 generation is the mid-cycle refresh of the 996 that was launched in 2002.   One of the biggest complaints of the 996.1 was that its styling was too similar to the Boxster.   The front end of the 996.1 was actually identical, thanks to cost cutting measures by Porsche.  The 996.2 included differentiating features such as revised headlights taken from the Turbo model, front and rear bumpers, interior changes, as well as an engine displacement increase from 3.4 to 3.6 litres.   Additional models were also added for the 996.2 lineup.  The wide-body model designated the C4S (Carrera 4S), GT2, GT3 as well “S” versions and factory power packages, often referred to as “X51” options.  Some of the model and engine-specific areas we will look at when performing a Riegel Service Inspection and a Pre Purchase Inspection on a 2002 – 2004 (2005 Cabrio) model of 911 are:

• Review any customer or seller supplied Service History documents.   We will give you our feedback and recommendations.   Example:  If there is no history of a brake fluid flush, we recommend this service every 2 years.
• 3.6 non-turbo engines are equipped with single-row IMS (Intermediate Shaft Bearing).  If there is no Service History of the IMS bearing being replaced, we recommend replacing it replacing it every 5 years/50,000 km’s.  The transmission is removed for the IMS Service.  At this time the RMS (Rear Main Seal) is also replaced.  The clutch and flywheel are also inspected closely at this time.
• 996 “M96” with engine code #661 14165 and above have single-row IMS bearings
• 3.6 non-turbo engines are also at risk of scored cylinder bores.  This is due to a combination of several factors including frequent cold starts, poor warm-up driving habits, infrequent Oil Change intervals, failure of the Lokasil cylinder wall coating, and failure of the coated piston skirts.  Cylinders 6, 5, 4 (in that order) seem to be most vulnerable to Lokasil cylinder wall coating failure.  We recommend adding a Bore Scope Inspection to the Pre Purchase Inspection.   Beware, not all Bore Scope inspections are equal.   The quick method involves using a bore scope camera through each of the spark plug holes to inspect the cylinder walls (approx 3 hours).   However, this only inspects half of the cylinder wall in each cylinder.   The more thorough approach is to also inspect the cylinder walls from the Oil Sump.  This includes removal of the oil pan.  
• Note that 996 Turbo and 996 GT3 cars are equipped with the “Mezger” designed engine.  The above-mentioned IMS, RMS and Bore Scoring issues do not apply to the Mezger engines
• Many higher-mileage examples of the 996 have had some or all of the above serviced, making Service History documents that much more important.
• Another key item to inspect and service is the Air Oil Separator (AOS).  Air Oil Separators (AOS) are a routine Major Service item, typically requiring replacement at 50,000 – 80,000 km intervals.   You will know when your AOS is in need of replacement, due to heavy smoke/oil burning at startup.