Soaringman

99 duel row, 80k miles

philooo

2003 Carrera 2, 45k miles, original IMS.
Transmission was dropped to fix RMS but the IMS flange showed no sign of leak AND most importantly I am still under extended warranty so I had to keep the IMS if I wanted to keep it intact.

KrazyK

With the failure rate poll right at 10% and most experts saying its a wear item, why not change it at every clutch job? Its too cheap and easy not to.

Ben Z

I would agree, but the single-row LN bearing (which most of us have who had it done prior to this year) is recommended for a 4 years/50,000 mile service interval. Maybe if one tracks the car a lot and/or is really rough on clutches it might need replacing that often, but for most of us I don't think it would. So it becomes a case of the tail wagging the dog.

996pp

With the number of 996's built and only 5% or hell even 10% failure rate your chances of getting hit by a bus walking in LA streets is alot more. So there are bigger problems to keep me up at nights i dont worry a single bit.

mcbit

... and those would be the people selling the replacements?

csubtil

04 C4S Cab, original IMSB, 77k miles.

Replaced the clutch in 2012 at 69k miles, replaced RMS and IMS flange but car was under warranty at the time so had to keep the original IMSB.

Warranty expired past February.

Considered ordering a replacement IMSB but I am afraid of the installation process. There aren't experienced techs in IMSB replacement in Portugal. So the "cure" could be more risky than taking my chances with the original IMSB.

IMSB failure did happen to 2/3 early 996 3.4L here in Portugal but never heard about a failure in a 996 3.6L around here (not even in portuguese Porsche forums, or at the Lisbon OPC where a good friend of mine works or the Portuguese Porsche Club).

Most 996 engine failures around here are due to crank main bearings failures (know of 7/8 cases).

CS

porsche951

Agree. These sellers of replacement bearings have made quite an industry out of the paranoid masses.

DaveCarrera4

why on earth would anyone believe this is statistically correct? Don't you think people with the IMSB problem search the internet and find this site looking for answers and fill out the poll?

2002 Turbo - Basalt Black Metallic / 2003 Carrera 4S - Speed Yellow / 1955 356 Continental 1500 - Rust Red

particlewave

This...

'99 986, 88k miles on original dual row. I won't change it because I'm not a hypochondriac. Maybe if I ever do the clutch, but that's a big maybe.

As I've said before, based on observation alone, it is much more likely that you will total your car in a wreck than have an IMSB fail.

Just drive the damn thing

5CHN3LL

97.2% of statistics on the internet are made up...

The odds of being hit and killed by a bus are one in thirteen million...just SLIGHTLY lower than the 1-in-20 to 1-in-10 chance of having a 996 in which the intermediate shaft bearing fails.

I don't worry a single bit either - I replaced the bearing. I honestly don't understand how people shrug this one off - the risk vs. reward (a few hundred bucks spent vs. $10K plus saved) makes this a straightforward decision for me.

I agree that spending money out of paranoia is stupid. The settlement agreement (or some of the supporting documentation, I don't recall which) included statistics from Porsche estimating the number of failures for single-row bearings up to 10%, moving this issue out of the realm of paranoia into the realm of fact. Failing to act because one chooses to categorize a known issue as paranoia is just as irresponsible as spending money on something without performing the due diligence to know whether it's warranted.

You realize that the number of 996's produced is irrelevant for this statistic, right?
If you prefer not to update the bearing, that's fine - but suggesting that the odds are lower than they really are isn't very responsible when you're posting that opinion in a forum used by many, many people as a technical resource.

5CHN3LL

The annual odds of having a "reportable" accident is approximately 5.5% (annualized). NHTSA records show that one out of every seven accidents results in a total loss. So, the odds of totaling your car in any given year are ROUGHLY 0.78%. Put differently, a 996 is about 13 times more likely to suffer an IMSB failure than you are to total your car next year.

I appreciate that folks are trying to reduce 996-related hysteria, but just making sh*t up isn't the way to go about it.

I'm not a hypochondriac either, but if my MD told me I had a 10% chance of having a fatal heart attack next year, I'd start eating baby aspirin for breakfast.

particlewave

The ego is a funny thing.
People will defend their choices to the death
You and I both. I respect your choice, but I don't agree with it and will defend mine.

As I very clearly said, my statement was based on observation.
I see many more posts about wrecked M96 cars than I do about IMS failures.

I'm just not one of those people that let fear control my decision making process and even if I did, I don't buy into the hype, so I'm not scared
I might die of a violently explosive fart tomorrow, but I'm not going to lose any sleep over that possibility tonight.

5CHN3LL

Heh. Noted. As far as death - sure, I'm OK that I spent the money, but this ain't the hill I'm dying on.

People can do whatever they want vis-a-vis their own car - I just don't like seeing "statistics" getting thrown around when they're either (a) bogus or (b) unrelated.

I know that my 996 has a 100% chance of dying someday, and replacing the IMS bearing does nothing to change that. I just elected to treat an area that's known to be a problem so I can keep it around long enough to (hopefully) have it die from something else. I didn't bother with the IMSB upgrade on my Boxster, as frankly I didn't care about it as much as I do my 911. Even if a full 10% of M96-powered cars really do suffer from IMSB-related issues, the other 90% have to die somehow.

Personally, I'd prefer to have my car die in a ditch - backwards, on fire - than from something mundane like a bearing.

particlewave

Well said.

I'm not at all saying that my viewpoint is any more correct than anyone else's, but simply stating my view and the reasons for it.

Now it's going to bite me in the ****...I can feel it, haha!
If my engine grenades, I've got no one else to blame