Porsche 996 Reliability & Problems

The Porsche 996 is the chassis code for the 911 Carrera produced from 1997 until 2006. The base model Carrera, 4, 4S, Targa, and Turbo versions were all replaced by the Porsche 997 in 2004. However, the Turbo S, GT2, and GT3 versions of the 996 remained in production until 2006 and were replaced by the 997 in 2007.

All 996 Carrera’s came in either 3.4L or 3.6L engine configurations. Base and lower end models initially received a 3.4L naturally-aspirated flat-six until 2002 when all engines were increased to 3.6L. The 996 Turbo, Turbo S, and GT2 versions of the Carrera received a twin-turbocharged version of the 3.6L.

Despite the varying engine sizes and aspirations, all Porsche 996 Carrera’s used the M96 engine. In addition to the 996, the M96 engine was also the primary engine used in the 986 Boxster.

While the M96 can be a reliable engine, the Porsche 996 usually gets a bad reputation for reliability due to a couple avoidable, yet expensive to fix, problems. This guide is going to discuss common Porsche 996 problems, overall reliability, and discuss which 996 years to avoid.

Porsche 996 Common Problems

• IMS Bearing Failure
• Rear Main Seal Leaks
• Cylinder Cracking & Scoring

Porsche 996 problems are fairly limited. However, the few problems it does face can all lead to significant repairs or complete engine failure. The bad reputation for 996 reliability is predominantly caused by the cost to repair the problems when they occur. While the percentage of cars that actually experience these issues is fairly low, the expensive cost to fix them causes the issues to be exacerbated on the internet.

With that being said, these are serious considerations when looking at buying a Porsche 996. Fortunately, the majority of these problems can be avoided with some preventative maintenance. We’ll cover each of these problems and how to prevent them, but for a more detailed explanation on each problem, you can check out this M96 engine problems article.

1) Porsche 996 IMS Bearing Failure

When searching for 996 Carrera reliability, the IMS bearing is probably the most prominent and talked about problem. There is a bit of debate around the IMS bearing and “when it was fixed”. We’ll break down the important points here, but first let’s discuss what the IMS bearing is and why it fails.

The IMS bearing is the intermediate shaft bearing. It supports the intermediate shaft which is near the flywheel and is designed to drive the camshaft off of the crankshaft. The bearing is plagued by two issues: weak materials, and lack of lubrication.

First off, the metal used to produce the IMS bearing is relatively weak which causes it to fail. It most commonly fails due to its age, rather than the amount of miles on it. Therefore, any 996 that hasn’t had its IMS replaced is at a heightened risk of failure. Secondly, the IMS bearing doesn’t receive adequate lubrication. Therefore, if you ever run low on oil the bearing is starved of lubrication and can therefore fail.

When the bearing fails it requires the engine to be completely torn apart, usually resulting in a full rebuild. The alternative option is to drop in a replacement engine. Either route you go is very expensive which is why this problem is heavily discussed online.

Fortunately, you can prevent IMS bearing failure by upgrading to a ceramic bearing, although this usually costs a few thousand dollars in labor.

When Did Porsche Fix the 996 IMS Bearing?

Two different IMS bearings were used from 1996 until 2005. The first one was used up until some time in the early 2000’s. The initial bearings had bad seals on them which deteriorated over time leading to failure. All the failures of the early bearings prompted Porsche to redesign them in early 2000.

However, the 2000-2005 IMS bearings are actually considered to be the weakest bearings of them all. In mid-2005 a third IMS bearing was implemented and is considered to be the strongest of them all.

Therefore, the most reliable years for the Porsche 996 are 1997-1999 and 2005-2006.

2) Rear Main Seal Oil Leaks

The rear main seal sits in between the crankshaft and the clutch/gearbox. Its job is to prevent oil from leaking out of the crank case and getting into the transmission. The seal is prone to failing over time usually due to a lack of lubrication. When a 996 isn’t driven very frequent the rear main seal can dry out and deteriorate causing it to leak.

A leaking rear main seal can take out the clutch and transmission if it isn’t caught soon enough. The seal is a very expensive part but it requires the transmission to be dropped to replace it which can make it labor intensive.

996’s that aren’t driven frequently or have sat for long periods of time are most prone to RMS leaks.

3) Cylinder Cracking & Scoring

When the M96 engine overheats it is prone to cracking the cylinders and liners. Cylinder scoring is usually caused by a lack of lubrication. While these two issues are somewhat common they are mostly caused by poor maintenance.

Changing your oil frequently and making sure the engine is always topped off on coolant will go a long way in preventing these issues. So while these are issues we generally don’t count them against the 996 since they can be prevented through proper maintenance and care.

Porsche 996 Reliability

The biggest reason the 996 Carrera receives a bad rap for reliability is because of the IMS bearing. While 2000-2005 models are most prone to failure, the earlier models fail frequently as well. One problem doesn’t make a car unreliable, but unfortunately, this one problem can cause thousands of dollars in repairs with the need for a rebuild or new engine. Therefore, it’s fair to hold this problem against the 996.

Fortunately, the bearing issues are preventable with an upgraded IMS bearing. While this costs a few grand in labor it can save the need for a complete tear down and rebuild. Considering these issues have been around for quite some time, a lot of 996’s on the road today have upgraded bearings.

A Porsche 996 with an upgraded IMS bearing gets an above-average reliability rating from us. Without the bearing upgrade it gets an average rating. Rear main seal oil leaks can be caught early on, only requiring replacement of the seal and not causing damage to the transmission. And cylinder issues can be prevented through good preventative maintenance.

What Porsche 996 Years Should You Avoid?

2002 and later models tend to be more desirable due to the facelift. Additionally, lower end models from 2000 and onwards are also more popular due to the larger 3.6L engine. So, which years to avoid certainly depends. It’s common to avoid the first year or two of a model as most issues will arise during this time period and be fixed subsequently. However, these years have stronger IMS bearings than the later more desirable models.

Our general advice is that any 996 with an upgraded IMS bearing is fair game. Beyond this it’s just personal preference.

Avoid: 1999 Porsche 996

1999 is the earliest model year 996 911 you will find in the United States. While these cars were produced as early as 1997, the first to hit the US were model year 1999 versions. So in essence, these are the first year production units and therefore have the most problems.

While the IMS bearing on the 1999’s is proven to be a little bit stronger than subsequent years, there were various small problems that affected the 1999 models that were fixed in later years. The 1999 models also had the 3.4L engines which are a bit less powerful than the later 3.6L models. Additionally, a lot of “comfort” features were added to the 996 in 2002 that weren’t present in the 1999 versions.

However, there are a lot of enthusiasts on the internet whose favorite 996’s are the 1999 models with build dates in mid-1998.

Avoid: 2000-2001 996’s Without IMS Upgrades

2000-2001 models are pre-facelift models which are a bit less desirable. While these years have the bigger 3.6L engine, they also have the weaker IMS bearing. Additionally, they lack a lot of the comfort features that were added in the 2002+ facelifted models.

However, these model years did have a number of small improvements over the 1999 year. Part of it comes down to opinion, but if IMS bearings are fixed on all of them, we would opt for a 2000-2001 model. We would choose a 1999 with the IMS bearing fixed over these years without the IMS upgrades.

With this said, there isn’t much difference between a 2001 model and a 2003 model in terms of reliability. The bearings are the same, the later model years are just more desirable.

The failure rate is estimated to be about 10% on 2000-2005 models. However, the likelihood for failure is probably a lot higher today if you have one of these without the IMS upgrade.

Porsche 996 Reliability Summary

The IMS bearing is the predominant reason the 996 is considered unreliable. Rear main seal replacements aren’t terrible considering it’s a Porsche, and cylinder issues are mostly caused by poor maintenance. Therefore, any 996 with an upgraded IMS bearing is going to be a pretty reliable one. However, keep in mind 996’s are pretty old nowadays which means you should expect for higher maintenance costs. Oil leaks, hoses, belts, water pumps, ancillary engine systems, and so on tend to become problematic as cars age. This is true for Porsche’s too and the older they get the more expensive they tend to be to repair.

What 996 years to avoid is honestly a personal preference. I’d avoid anything without an upgraded IMS bearing, unless you are comfortable spending the money to upgrade it yourself. A lot of folks love the earliest 1999 models you can get, and a lot of people don’t like the 1999’s since they are the first model year. Facelifted 2002+ models tend to be in higher demand, but this is also just because of personal preference.

Overall, Porsche 996 reliability doesn’t differ by much once the IMS bearing issue is resolved. Do note however that a 1999 996 is 5-7 years older than the later models and therefore could run into various maintenance items more quickly or frequently simply due to age.

What’s your favorite Porsche 996 year?