m3driver

Wow, who would have though of that? all along I thought they were the same thing

Slakker

Was I the only one that saw the sarcasm on M3's initial question? It was so thick it was dripping off the letters. Lol.

Southern Man

My local dealer told me they had never changed an IMS bearing! I was shocked at the time, but it seems like that is the norm. I don't take my car there. The cost was the initial reason, but I've been unimpressed with their 996 knowledge when I've tried to buy parts from them.

Macster

Pretty normal. If the IMSB fails under warranty the SOP is to replace the engine. I know of only one case where an IMS (and B) was replaced under warranty at a dealer.

If the IMSB fails outside of warranty and there is even the possibility of some "goodwill" the owner usually balks when he gets the quote to remove and tear down the engine to determine just what went wrong and to determine if the engine is even salvageable. If the problem is not on the "good will" (secret) list or there are mitigating circumstances (overrevs signifying a "money shift") the owner is out the cost of the engine removal and tear down and then is facing no good will and possibly an engine replacement.

beetleything

Yep - gets lost in translation on the internet........

porsche951

Makes sense to me that Porsche won't replace the bearing with an aftermarket one. They still cling to the belief that there was nothing wrong with the original.

993James993

I just had a PPI done on a '99 at a Porsche dealership. The service advisor told me that he had worked on these cars for 22 years. He indicated that this is not a sudden failure. You will hear a 'loud rotational whine' before failure. If you ignore it and continue to drive the car, expect the worst. If you shut it down and tow it to a repair facility you will avoid the failure. He did acknowledge that the IMS replacement preformed by an independent is the only solution as Porsche will require more expensive repairs. Even so, the aftermarket replacement is only good for 30-50K miles. Based on my research I believe that only 1% of '99's had this failure (4% for later cars). For a car that is maintained I have come to believe that this is certainly manageable.

gnat

Other than telling you to go to an Indy, none of that was correct

Once a bearing is shedding metal, it has failed. When a bearing has failed, the motor has to be torn down and cleaned. Anything less runs a good chance of debris remaining in the motor to do further damage down the road. Simply flushing the oil does not fix the problem.

If you are lucky and catch metal in your oil before the catastrophic failure, that just means more parts may be salvageable. The time between shed metal in the oil and catastrophic failure depends on your bearing and your luck. A dual row bearing will last the longest in the shedding phase. A single row has minimal time between the events. The only sound you hear associated to the IMSB failure is the sound of your motor catastrophically failing. When you hear "the marbles", it's done.

The Solution is just that, a solution. It has no interval. The LN Retrofit has a service interval of 50-75 (I want to say it's 65, but this is from memory), not 30-50. I can't speak to the roller options.

ZuffenZeus

They serve a special form of Kool Aid in their fancy lounges.

993James993

Hi Gnat,

Thanks for your post and your insights. Regarding the lack of any warning sound, do you know this per personal experience? Or by the experience of others? I am not disputing your comments, just trying to understand this issue. I have only recently started studying the 996 cars and want to learn as much as I can.

Thank you,

Jim

gnat

Jim, No personal experience. I chose to not panic (benefit of being an original owner and knowing every mile it has seen) and waited until the transmission needed to be rebuilt. Our 01 turned out to have a dual row which was perfectly healthy.

My information comes from following the issue for too many years now and most of it is based on the information that Jake Raby has provided us over that time.

The first part of my comment (when it starts shedding metal, it has failed) is probably the most contentious part of what I said and it comes straight from Jake. If you follow the IMSB threads you'll find lots of people saying some form of "I found metal in the oil, but caught the bearing before it failed" and they then go on to state that a replacement bearing was installed and "all is good".

We have seen, however, too many people (usually shortly after buying a car with a recent bearing replacement) come in and ask about their engine failure which their Indy chalked up to the IMSB.

If you follow any rebuild threads (I believe Ashai's "blown motor" thread has been bubbling up to page 1 lately) you can see examples of how and where debris can get caught in the engine that is not going to simply flush out. The shed metal from the bearing can/will get stuck in there and then at some point down the road it comes free and starts circulating again to do it's damage. This is why no LN certified installer will put a new bearing in a car that shows signs of failure. It is also why some of us believe it's best to buy a car that hasn't had it's bearing replaced (so you know for sure and get to make all the decisions).

There is a lot of panic and fear around the 996, but they are great cars (especially for the price). Good luck on your hunt, it's worth it.

mjdavis

If you are in central/southern NJ you should call Yurii at Polar Porsche. He has done a ton of IMS replacements. If you're closer to NY try Michael at Formula Motorsports in Queens. If you can go north, try Spencer *** at Speedsport, or Daniel Jacobs (a bit farther north/east, but I believe they were involved in the initial replacement bearing development).

Sneaky Pete

Gnat is correct....there is no sound. Think of a massive heart attack..you are dead before you hit the ground. It happens but they are rare. Hit that little search button in the upper right and enjoy a year or two worth of reading and crapping yourself.

Like others have said, if you plan on tracking take care of the oil system. I was one that did not and learned my lesson

Imo000

If your engine is a '99, you have a double row Intermediate Shaft Bearing and I would LEAVE IT ALONE.

808Bill

So far I've gathered that a 99 with original dual row is the one to find for me.
I plan to start with an oil change and have the old oil analysed. Then follow that course for the rest of the oil changes at 3-5K miles.
I don't have any certified IMSB techs in the state. I am a car nut with basic tools, I have no fear of pulling the motor and doing my own work but, I am not a mechanic...

Other then the RMS, AOS and water pump, what should I plan on or budget for right out of the gate?