Which Porsche Years Have IMS Bearing Problems?

Porsche IMS bearing problems primarily affect 1997–2008 Porsche Boxster, Cayman, and 911 models equipped with M96 and M97 engines. The highest-risk years are 2000–2005, when Porsche used the smaller single-row IMS bearing that was reported to have an approximately 8% failure rate during the warranty period. Earlier 1997–1999 engines generally used the stronger dual-row bearing, while 2006–2008 engines use a larger, non-serviceable IMS bearing. Beginning with the 2009 model year, Porsche’s MA1 (9A1) engine eliminated the intermediate shaft and IMS bearing entirely.

In This Guide, We Cover:

• Porsche IMS bearing problem years at a glance
• Porsche 911 996 and 997 IMS bearing problem years
• Porsche Boxster 986 and 987 IMS bearing problem years
• Porsche Cayman 987 IMS bearing problem years
• Why 2005 is a complicated IMS bearing year
• Whether you should buy a Porsche from an IMS problem year
• How to reduce the risk of IMS bearing failure
• What changed with the IMS bearing for 2006–2008
• When Porsche eliminated the IMS bearing
• Whether 996 and 997 Turbo, GT2, and GT3 models have IMS bearing problems
• Understanding the cost and risk of IMS bearing failure
• Porsche IMS bearing FAQ

Porsche IMS Bearing Problem Years at a Glance

Model Years	Models	Factory IMS Bearing	Relative Concern	What Owners Should Know
1997–1999	Boxster 986	Dual-row	Lower, but not zero	Serviceable; preventative replacement recommended
1999	911 996	Dual-row	Lower, but not zero	Serviceable; preventative replacement recommended
2000–2001	Boxster 986 / 911 996	Dual-row or single-row	Varies	Bearing type cannot reliably be determined by model year alone
2002–2004	Boxster 986 / 911 996	Single-row	Highest concern	Serviceable; preventative replacement recommended
2005	Boxster 987 / 911 996 or 997	Single-row or larger non-serviceable bearing	Transition year	Verify the actual bearing fitted to the engine
2006–2008	Boxster/Cayman 987 / 911 997.1	Larger non-serviceable bearing	Lower failure rate, but not immune	Cannot normally be replaced without engine disassembly
2009+	Boxster/Cayman 987.2 / 911 997.2	No IMS bearing	Not applicable	MA1/9A1 engine eliminated the intermediate shaft

Why Porsche IMS Bearing Failures Matter

A failed IMS bearing can result in loss of camshaft timing, internal engine damage, and a costly rebuild. For engines fitted with a serviceable factory IMS bearing, preventative replacement is therefore recommended rather than waiting for symptoms to appear. Replacement options include the IMS Retrofit and IMS Solution, with the IMS Solution replacing the original ball bearing arrangement with an oil-pressure-fed plain bearing.

Frequent oil changes and the use of an appropriate high-quality engine oil are also important for overall engine health. For LN Engineering’s recommended lubricant strategy, see our Porsche engine oil guidance.

Porsche 911 996 and 997 IMS Bearing Problem Years

Depending on the model year, Porsche used different IMS bearings, with some years being more problematic than others:
 

• 1999 Porsche 911 996.1 – Dual Row IMS Bearing
• 2000-2001 Porsche 911 996.1 – Dual Row or Single Row IMS Bearing
• 2002-2005 Porsche 911 996.2 – Single Row IMS Bearing (some late 2005 builds may have the larger, non-serviceable IMS bearing)
• 2006–2008 Porsche 911 997.1 – Larger, Non-Serviceable Single Row IMS Bearing

The most problematic years are 2000 through 2005, when the factory single-row bearing was used. The single-row IMS bearing had a reported failure rate of approximately 8% during the warranty period, while the earlier dual-row bearing had a substantially lower reported rate. The warranty-period figures should not be interpreted as lifetime failure rates.

When the IMS bearing fails, it results in a loss of camshaft timing that can cause severe damage to the engine, including bent valves and debris. Replacing the intermediate shaft and addressing any collateral damage requires a complete engine disassembly. Therefore, factory serviceable IMS bearings should be addressed as part of preventative maintenance, similar in concept to other time- and mileage-dependent engine service items.

IMS bearing failures have historically been associated with vehicles that are driven infrequently, sit for extended periods, or are used predominantly for short trips. In newer Porsche 911 models with the larger, non-serviceable 2006–2008 IMS bearing, the grease seal should be removed to extend the life of the original bearing because replacement requires complete engine disassembly.

Porsche Boxster 986 and 987 IMS Bearing Problem Years

Like with the Porsche 911, the Boxster IMS bearing problem years vary from year to year depending on which IMS bearing was used by Porsche:

• 1997-1999 Porsche Boxster 986 – Dual Row IMS Bearing
• 2000-2001 Porsche Boxster 986 – Dual Row or Single Row IMS Bearing
• 2002-2004 Porsche Boxster 986 – Single Row IMS Bearing
• 2005 Porsche Boxster 987 – Single Row or larger non-serviceable IMS bearing depending on engine/build
• 2006–2008 Porsche Boxster 987 – Larger, Non-Serviceable Single Row IMS Bearing

For the Boxster, the IMS bearing problem years where failure of the original intermediate shaft bearing is most likely are model years 2000 through 2005. As with the 911, models with a serviceable IMS bearing should have the bearing addressed as preventative maintenance. Boxster models with the larger, non-serviceable single-row IMS bearing should also have the grease seal removed.

Porsche Cayman 987 IMS Bearing Problem Years

The first-generation Porsche Cayman was introduced for the 2006 model year. All 2006–2008 Cayman models use the larger, non-serviceable IMS bearing. Although this bearing has proven more robust than the earlier single-row bearing, it is not immune to failure and cannot normally be replaced without complete engine disassembly. Removing the factory grease seal allows engine oil to better lubricate and cool the original bearing.

Why Is 2005 a Complicated Porsche IMS Bearing Year?

2005 was a transition year for Porsche IMS bearings. Many 2005 engines use the serviceable 6204 single-row bearing, while some later engines received the larger 6305-series bearing used in 2006–2008 models. For that reason, model year alone should not be used to determine which IMS bearing a 2005 Porsche has.

A Porsche factory replacement engine can also have a different IMS bearing than the car originally received. Replacement engines manufactured in or after model year 2006 generally received the later, larger IMS bearing.

Should I Buy a Porsche From an IMS Bearing Problem Year?

An affected model year should not automatically disqualify a Porsche from consideration. What matters is which IMS bearing the engine has, whether it has already been upgraded, the quality of the installation, and the overall condition and service history of the engine. Cars with original serviceable IMS bearings should be evaluated for preventative replacement, while 2006–2008 engines require a different approach because the larger bearing cannot normally be replaced without engine disassembly.

What Can Be Done to Avoid IMS Failures in Cars Affected by IMS Issues?

Learn more about How to Identify and Fix the Porsche IMS Bearing Problem and How to Determine When and if your Porsche IMS Bearing Needs to be Replaced.

Replacement options include the IMS Retrofit and IMS Solution, the latter replacing the problematic ball bearing with an oil-pressure-fed plain bearing, which is the only permanent solution. All other ball or roller bearing replacements, including the IMS Retrofit, have service intervals and require future replacement based on time and/or mileage requirements.

On engines where the IMS bearing is not serviceable, the grease seal should be removed to allow the engine oil to properly lubricate the original IMS bearing. This includes all Porsche Boxster, Cayman, and 911 models from 2006 through 2008 and all replacement engines manufactured by Porsche in or after model year 2006. Learn more about the non-serviceable 06-08 Porsche IMS bearing.

In What Year Did Porsche Fix the IMS Bearing Problem?

Porsche improved the IMS bearing beginning with the 2006 model year, but did not completely eliminate the IMS bearing until 2009. For 2006–2008 engines, Porsche adopted a larger, non-serviceable 6305 single-row ball bearing that provided load capacity similar to the original dual-row bearing. Its larger diameter also increased bearing speed, which is beneficial to bearing longevity.

The drawback is that the bearing diameter is larger than the opening in the engine case, so the bearing cannot be removed without complete engine disassembly. Porsche also retained a grease seal like the earlier IMS bearings, which prevents engine oil from properly lubricating and cooling the bearing even though it is submerged in engine oil during normal operation.

Although significantly more robust than the single-row IMS bearing used from 2000 through 2005, the larger 2006–2008 IMS bearing is still not immune to failure.

Beginning with the 2009 model year, Porsche redesigned the engine for the Boxster, Cayman, and 911 to eliminate the intermediate shaft completely. The camshafts are now directly driven off the crankshaft in the MA1 (9A1) engine.

It is worth noting that the aircooled Porsche Mezger engine which was later adapted for use in the Porsche 911 GT3, Turbo, and GT2 successfully retained its intermediate shaft through the end of production. This design utilized oil-pressure-fed plain bearings.

Do Porsche 996 and 997 Turbo, GT2, and GT3 Models Have IMS Bearing Problems?

The water-cooled Porsche 996 and 997 Turbo, GT2, and GT3 models use Mezger-derived engines rather than the M96/M97 engine family. Although these engines also use an intermediate shaft, the shaft is supported by pressure-fed plain bearings rather than the sealed ball bearing associated with M96/M97 IMS failures. As a result, these models are not affected by the same IMS bearing problem discussed on this page.

Understanding the Cost and Risk of IMS Bearing Failure

If your Porsche falls within the 2000–2005 range, it is at higher risk because these model years commonly use the smaller single-row IMS bearing. Preventative service should be considered before bearing failure occurs.

• 8% failure rate for single-row IMS bearings in 2000–2005 models under warranty
• IMS bearing risk does not disappear simply because a vehicle has survived beyond the original warranty period
• No factory IMS bearing is immune to failure

Proactive IMS bearing replacement costs a fraction of an engine rebuild. Protect your Porsche and your wallet—schedule your IMS upgrade today. Drive with confidence knowing your Porsche engine is protected.

Porsche IMS Bearing Problem Years FAQ

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