What is IMS Bearing?
Before diving into the Porsche IMS bearing problem, it’s important to first understand what IMS is. IMS is short for ‘intermediate shaft.’ It is a shaft that extends from the front of the engine to the rear. It is powered by the mechanical rotation of the crankshaft and drives the camshafts using gears.
When Porsche introduced the Boxster engine in 1997, it included a sealed bearing to support the intermediate shaft on the flywheel side. This bearing is what is commonly referred to as the IMS bearing. It’s the root cause of the infamous Porsche IMS-related engine problems that plague the 1997-2008 Cayman, 911, and Boxster models.
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What is the Porsche IMS Bearing Failure Issue?
As mentioned earlier, the intermediate shaft is supported by a sealed ball bearing. Porsche filled the bearing with grease to ensure it stays lubricated. Over time, the seal becomes hard and starts to fail. This causes the oil that submerges the intermediate shaft to find its way into the bearing.
If the oil is contaminated, the impurities also find their way into the bearing. The oil then starts to wash out the original grease. With contaminants and no fresh oil, the bearing starts to wear and the seal fails completely.
This then causes considerable damage to the intermediate shaft which then becomes unserviceable. Debris from the damage also tends to find its way into other parts of the engine. In extreme cases, the camshaft timing changes and causes the valves to get in contact with the piston. The valves then bend and fail.
What Causes IMS Bearing to Fail?
There are several contributing factors that cause IMS bearing failure in the 1997-2008 Porsche Boxster, Cayman, and 911 models. The factors include:
- High oil temperatures
- High moisture and fuel content in engine oil
- Poor or insufficient lubrication
- Long drain intervals
- Spalling, as a result of normal fatigue, also occurs when the bearing has reached the end of its lifespan.
The most common reason, however, behind bearing failure is contamination by small metallic particles. The particles may have been left behind after a previous mechanical failure. They get suspended in oil and find their way into the IMS bearing and can sometimes leave behind dents in the steel raceway.
When the balls roll over the raised area surrounding the dent, the loading at the ultra-high point surpasses the strength of the steel and causes it to crack. This then leaves behind pointed depressions.
The cycle continues and eventually leads to early bearing failure. The pitting and wear caused by contamination from foreign objects is the most common cause of Porsche’s bearing problems. It accounts for about 70% of all premature bearing failures.
What year Porsches have IMS problems?
All 1997-2008 Boxster, Cayman, and 911 Porsche models that run on the M96 or M97 engine are prone to the IMS bearing problem. They all come with an intermediate shaft (IMS) that is supported by a sealed ball bearing.
For the 2000-2005 model years, Porsche included a dual row intermediate shaft bearing. Years 2001 and 2002 used either a dual row or single row IMS bearing. The automaker switched to a larger single row IMS bearing for the 2006-2008 model years. The dual row IMS bearing in the 2000-2005 models was discovered to have an 8% failure rate when compared to 1% for the single row bearing used in 2006 – 2008 models.
The information obtained from the Eisen IMS Class Action Lawsuit showed that the single row ball-bearing put in the 2000-2005 model years was the most problematic. The dual row ball bearing that came after was more robust. It had twice the load capacity. However, despite it being stronger, it still failed.
In 2009, Porsche revised all Porsche Boxster, 911, and Cayman models and switched to the MA1 engine. This eliminated the use of the intermediate shaft completely. The camshafts were driven directly off the crankshaft.
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How to know if your Porsche is at risk of IMS Bearing Failure
It’s not clear how long it takes for the IMS bearing to fail. Some engines have had to undergo repair and replacement at just 3,000 miles. Others have lasted beyond 200,000 miles. In most cases, the first symptom of failure is fatal engine damage.
The ball-bearing seal that Porsche uses to protect the IMS bearing works to keep debris and wear within the bearing. This goes on until the bearing reaches a point of complete failure. Once the grease seal wears out, it allows debris to exit from the bearing.
The most common symptom is seeing small metallic particles in the oil filter. They are ferrous and look like silver glitter. If you were to pass a magnet over the filter, it would pick them up. It’s important to note that the absence of debris does not rule out the possibility that the IMS bearing could be about to fail.
For example, some 2000-2005 models with single row bearing have been known to show no symptoms before going into complete failure. This means that carrying out a filter inspection and oil analysis can, therefore, bring a false sense of security. It’s best to have your IMS bearing changed during scheduled maintenance before it starts to fail.
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Avoiding or Preventing Porsche IMS Bearing Failure
1. IMS Retrofit Kit
The best solution to prevent an IMS bearing failure is to have the original bearing replaced with an IMS Retrofit kit. This helps to minimize the risk of a catastrophic engine failure.
2. Remove original grease seal
Another attempt at preventing IMS bearing failure is to remove the original grease seal from the intermediate shaft bearing. This improves cooling and lubrication. It’s cost-effective and one of the most viable solutions for the 2006-2008 model year engines. These Boxster, 911, and Cayman models have an IMS bearing that is non-serviceable. The bearing’s performance can only be prolonged by removing the grease seal for better lubrication.
3. New IMS bearing
The other solution is to tear the engine down to gain access to the intermediate shaft and replace the existing bearing with an upgraded IMS bearing. Since this is a complex process that involves complete engine disassembly, many experts recommend going with the first option – removing the grease seal to help extend the service life of the bearing. This can be done whenever you’re having the gearbox out for a clutch job or when replacing the rear main seal.
4. Frequent oil changes
Many experts also recommend changing your oil frequently with quality 5w40 motor oil once the grease seal is removed. This should be done after every 5,000 miles or every 6 months. This is, however, still a subject under great debate. Also, driving your Porsche regularly and staying away from higher gears to keep revs over 2500-3000 rpm is a good start.
5. Magnetic drain plug
In addition to frequent oil changes, the use of a magnetic drain plug and regular inspection of the magnet and oil filter can help detect early wear and tear in the bearing. Ferromagnetic particles will appear as silver glitter and can be identified easily. If there’s larger debris, this is an indication that the IMS bearing has completely failed.
Nonetheless, doing an IMS bearing replacement is the most proactive measure that prevents failure. Replacement can only be done before complete damage. It is not an option once the engine has failed. This is because such damage may result in more engine failure as a result of collateral damage. Debris left behind may also contaminate the new bearing.
IMS Bearing Replacement
Up until 2008, replacing the original IMS bearing was not possible. This is because the original intermediate shaft bearing was meant to last the lifetime of the car’s engine without any service. There were no offers on a replacement IMS bearing upgrade.
For years, the only option available was to tear down the engine completely and fit in a new intermediate shaft obtained from Porsche.
a) IMS Retrofit Kit by LN Engineering
This changed in 2008 when LN Engineering came up with an IMS Retrofit procedure that showed how to change the original IMS bearing. Car owners could now replace the IMS bearing in Boxster and 911 engines with a stronger ceramic hybrid ball bearing.
The IMS Retrofit kit is the most trusted IMS Solution. It eliminates the problematic roller-bearings and ball-bearings and replaces them with a pressure-fed oil lubricated plain bearing like the one found in air-cooled Porsche models. Below are some of its pros and cons.
- Can be installed without engine disassembly.
- Has a zero failure rate.
- IMS Retrofit kits from LN Engineering are serial numbered, laser etched, and engraved for authenticity.
- Installation can be done in conjunction with other service maintenance to save on labor costs.
- Prevents catastrophic and costly engine failure.
- IMS Solution is trusted by hundreds of dealerships and independent mechanics worldwide.
- Replacement takes an average of 10-14 hours.
- High IMS bearing replacement cost.
- All engines must undergo pre-qualification before IMS bearing replacement.
More than 40,000 IMS Retrofit kits have been sold and installed worldwide. So far, there have been no confirmed cases of failure where the replacement of dual row ceramic bearings has been done by qualified professionals.
b) Porsche IMS Bearing Kits
After the Eisen Class Action lawsuit, Porsche eventually released its own IMS bearing replacement kit in 2017 with a similar ceramic hybrid ball bearing technology. This was, however, almost a decade after LN Engineering had released its own solution.
Like LN Engineering, Porsche opted for a ceramic hybrid bearing. In particular, the automaker used a sealed 6204 ceramic hybrid bearing with 52100 steel races and sintered silicon nitride balls. Below are the pros and cons of Porsche’s IMS bearing solution.
- 52100 bearing steel features high rolling fatigue strength and high wear resistance.
- Silicon nitride balls are thermodynamically stable.
- Bearings are highly resistant to corrosion and abrasion.
- No adhesive wear or cold welding
- Ball skidding is minimized thanks to lowered centrifugal forces in the bearing.
- Ceramic hybrid ball bearings can be costly
All 1997-2005 Boxster and 911 owners should have their IMS bearing replaced as a preventative maintenance measure. This is to prevent the disastrous engine failures that have plagued the M96 and M97 Porsche engines. Failure rates have been known to rise the longer the original IMS bearing remains in use.
c) IMS Solution
Apart from the two solutions mentioned above that include retrofit kits, there’s another solution available for Porsche owners. It is dubbed the “IMS Solution.” It uses a simple design to eliminate the problematic single row ball bearing that comes in the 2000-2005 Porsche models and the dual row bearing found in the 1997-2001 models.
This is by providing a plain bearing replacement that is pressure-fed and oil-lubricated at all times. Its design eliminates eleven wear components in the bearing system. With the IMS Solution comes a plain bearing, an IMS bearing flange, and an oil filter adapter assembly. The oil filter adapter filters all the oil and sends it to the plain bearing via a high-quality external oil line. The line then connects to the plain bearing through the IMS bearing flange.
Since Porsche’s original IMS bearing is not oil-fed, there’s no provision on the engine for an internal oil passage. This means that the engine crankcase needs to be modified. The modification provides space for the external oil line that comes in the IMS Solution. It is a permanent fix that doesn’t require any service intervals.
IMS Retrofit VS Solution
The decision on whether to go for an IMS Retrofit or IMS Solution depends on two factors – cost and how long you wish to own your car. With the IMS Retrofit kit, servicing and proactive replacement are required after every 6 years or 75,000 miles for the dual row and single row bearings. Installation is possible in conjunction with other service maintenance to save on labor costs.
When it comes to the IMS Solution, you get a permanent fix that comes with no service interval. It is designed to last the lifetime of your engine and is the best choice for those looking for an absolute fix to the IMS bearing failure issue. It also makes the most sense if you’re forced to rebuild your engine after failure.
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IMS Bearing Replacement Cost – How much does it cost to replace IMS bearing?
The average cost of doing an IMS bearing replacement is $3500 – $4500. In some cases, the repair costs can go up to $20,000. This varies with changes in regional labor rates and how much deferred maintenance is needed. Not all vehicles are healthy enough to have an IMS Retrofit kit installed.
This is why a professional needs to first carry out an IMS pre-qualification process. It could take several hours. About 20% of all cars end up failing the pre-qualification. One of the biggest mistakes that people make is assuming that all cars are qualified. Each and every engine is unique in its own way and needs close attention.
Once qualified, the IMS bearing replacement process takes 10-14 hours. This varies with the Porsche model in question. In Tiptronic 911 models, the technician is required to separate the transmission and the engine to gain access to the IMS bearing. Due to some additional tasks that are supposed to be done in preventative maintenance, it wouldn’t be a surprise if you were asked to pay more for replacement parts and labor.
Porsche eliminated the use of the IMS bearing in its cars in 2009. The company had also efforts to eliminate bearing failure in cars made between 2006 and 2008. Only a few models made in early 2006 still had IMS bearing problems.
A bad IMS bearing will produce rattling noises that can be heard coming from the engine compartment. This happens when you’re starting the engine and when you step on the accelerator.
The most common signs of IMS bearing failure are grinding and knocking noises coming from the engine. Leaking oil and metallic particles are also signs that parts have broken due to an IMS bearing failure.