All Boxster, Cayman, and 911 vehicles from MY1997 to MY2008, with the exception of Turbo, GT2, and GT3 variants, are susceptible to IMS bearing failure.
But over time, the types of bearings utilized changed, and some of them were more likely to fail than others. According to statistics, the Boxster 986 and 911 models built between model years 2000 and 2005 are the most likely to experience IMS bearing failure, whereas the odds are extremely low for a Boxster 987 or Cayman built after a stronger bearing was introduced in late 2005.
In terms of mileage, there is no clear trend in the failures; some owners were unfortunate enough to encounter IMS issues at less than 20,000 miles, while others assumed they were safe only to have the bearing fail at 130,000 miles. In summary, you should be aware of potential issues if you now own or intend to purchase one of the versions with the weaker bearing that were in use from 2000 until late 2005.
The base engine (3.6) bears the designation “M96,” and depending on your engine number, you may have the smaller IMS or the revised bigger bearing:
Engine (3.6) number M96/05 69507476 has the larger updated IMS bearing, while Engine (3.6) number M96/05 69507475 has the smaller IMS bearing.
The “S” Engine (3.8) is designated “M97” and features a choice of a smaller or bigger upgraded IMS bearing:
Engine (3.8) numbers beginning with M97/01 68509791 have the larger updated IMS bearing, whereas Engine (3.8) numbers up to M97/01 68509790 have the previous IMS bearing.
In This Article...
Ultimate Guide and Frequently Asked Questions for Porsche IMS Bearings
The IMS (middle shaft) of an M96 or M97 engine is supported by a sealed ball bearing. the bearing installed on the intermediate shaft by
Porsche offers an interval, replacement process, or replacement IMS bearing for
It was not able to replace or upgrade the original factory IMS bearing until LN Engineering.
inquiries to find out all there is to know about intermediate shaft bearings
and why the best IMS bearing Retrofit and Solution products are those made by LN Engineering
There are no controls that
Other than verifying the bearing after removing the flange, there are no tests that can be done to ensure that a car doesn’t have an IMS issue. However, this includes removing the transmission, clutch, and flywheel as well as performing preparation work on the engine.
All engines up to model year 2009 contain an IMS bearing, but very few of them ever experience a problem.
Even if replacing the IMS bearing in your car requires disassembling the engine, there are other options. If you want to talk, get in touch with me directly. 954-385-0330.
The motor will thereafter be destroyed!
Options quickly become scarce and expensive after an intermediate shaft bearing breaks. The ultimate best-case scenario (and least likely) is if only the intermediate shaft and bearings need to be changed, but even then, removing, inspecting, and disassembling the entire engine is still necessary.
In the worst case, IMS bearing failure can interrupt cam timing, which can effect the pistons and valves, shattering the valves, smashing the pistons, and causing other significant engine damage. The majority of the time, your only options are to completely rebuild the engine or replace it, both of which come at a hefty price.
IMS bearing problems’ warning signs and symptoms
A few red flags may indicate that your IMS bearing is deteriorating. The most noticeable one would be noises originating from your motor, such as knocking or grinding. If this is happening to your Porsche, the IMS bearings may be failing.
Other indications that something within your car has broken off include oil leaks or metallic shards in the oil. It’s possible that the IMS bearing is causing expanding damage to the rest of the engine in your automobile, which is why it’s now difficult for it to tow high loads.
Has the 2007 Cayman experienced IMS issues?
The IMS issue only affects vehicles manufactured in 2008 and earlier. Since the 2009 and subsequent engines lack an IMS, they are free of the IMS issue.
What does a Porsche’s IMS service entail?
If you had read the phrases “premature catastrophic engine failure” above, you would have wondered how a very small component could have the potential to instantly and seemingly without warning destroy an entire engine. We’ll briefly discuss what an IMS bearing is and how it works without getting too technical.
IMS stands for intermediate shaft, to start. The intermediate shaft, which goes through and exits from the front and back of the engine, is essentially a geared shaft. The purpose of the intermediate shaft is to employ those gears to indirectly drive the camshafts on either side of the engine by using the mechanical rotation of the engine’s crankshaft. But the 996 and 997 IMS-related “engine troubles” that are now well-known and notorious are not caused by the intermediate shaft itself. The then-radical and novel water-cooled “M96” engine created for the 996 was by no means a fresh development in terms of basic design or usage of an intermediate shaft. The horizontally opposed (sometimes known as a “boxer” arrangement) flat-six engines that are so famous for the Porsche 911 have really had an intermediate shaft for as long as the 911 has existed. The use of an intermediate shaft on Porsche’s flat-six engines had been well-proven up to this point in the long history of the 911’s development, both conceptually and practically. The problem (pun intended) with the introduction of the M96 and the initial production runs of the subsequently upgraded “M97” engines lies in the sealed cartridge-style ball bearings, sometimes known as the “IMS bearings,” that support the IMS.
Which Porsches are affected by the IMS bearing issue?
The intermediate shaft bearing, commonly known as an IMS bearing, has a significant failure rate in the Porsche 911 and Porsche Boxster from model years 1997 to 2005. Its build and design cause the bearing to prematurely fail, which causes a catastrophic engine failure.
When did Porsche stop using IMS bearings?
Not to pick on, but the 2009 model year marks a change in that Porsche fully did away with the IMS bearing. Although the IMS bearing was not completely abolished by the 2006-20008 (with the exception of a few very early model years that still had the leftover M96 engine), the failure of the bearing was essentially eradicated. I sincerely doubt that I have read about a single instance of an IMS failure on an M97 motor. It’s interesting to note that IMS bearings have been used in Porsche engines since the 996s. Every 911 from 1964 to 2008 had an IMS bearing, in actuality. Even the cherished Mezger automobiles, such as the Turbos and GT3s, lacked IMS bearings. They simply never fell short. The M96 motors’ failure was mostly the result of poor upkeep. It’s true that poorly designed seals permitted bearing failure in vehicles with little mileage and irregular oil changes. I have never saw an IMS bearing fail in a vehicle that was frequently driven and received regular/appropriate oil maintenance.
With Dwain Dement (the owner of Vision Motorsports), I had a lengthy conversation on the M97, M96, and 2009 direct injection motors. I even went on a tour of his engine manufacturing facility. Each year, Dwain produces around 100 M96 engines as well as almost as many M97 race motors. The IMS bearing is a genuinely trivial problem, which is funny. Any wear issues can be easily detected WELL before catastrophic failure with the right maintenance, etc. However, the majority of individuals simply follow the lore that is widespread online. The casting of the cylinders into the casing is the major problem with M96 motors that is frequently disregarded. They may crack with prolonged use or high mileage. Since their cases are thicker, M97 motors rarely experience cracking problems. According to Dwain, he has never witnessed an M97 motor’s IMS bearing fail. He claimed that the bearing is considerably bigger and stronger.
The M97 IMS failure rate is interestingly close to zero…even with rather subpar care. Additionally, due to how much larger the bearing is than its predecessor, it cannot be replaced until the engine case is opened. Since they are better for higher RPM and a little more durable than direct injection motors in terms of boring to bigger displacement, etc., Dwain employs the M97 motor for the majority of his race car engines. After each race, he conducts an oil study on every M97 engine he supports. It’s interesting to note that he rarely observes excessive metal wear until there has been a serious missed shift, which he notes using the Motec(r) system, which is far more accurate than the original DME.
Sorry for the rant, but I’ve written numerous articles about it, visited four engine shops, and spoken with a ton of mechanics and engine builders, including Dwain, Deiter (Andial), Tony Callas, and others. There are numerous misconceptions regarding IMS bearings, etc. I went directly to folks who see these motors and bearings on a daily basis rather than depending on what is written online or in magazines.
Personally, I believe that direct injection motors are given far too much credit. Think about all the troubles that VW and BMW are experiencing with that configuration. All day long, I would choose an M97 engine to save money.