I've been a lurker since 2020, but read this forum almost everyday. So, I have encountered an unexpected crossroad. The IMS bearing in my '05 C2S failed last Saturday at ~ 99,200 miles. I was operating on what I believed was an acceptable risk based on consensus that 997s could experience IMS failure, but it was less frequent than in 996s, and if the engine had more that 50K miles, then IMS failure was less likely to occur. I am a risk taker. I like being near the edge - but not over. Unfortunately, I should have had the bearing replaced when the clutch was replaced at 74K. IF YOU OWN A 997 AND HAVE NOT REPLACED THE IMS BEARING - IT CAN HAPPEN TO YOU!
Here is the event sequence: I left Aiken, SC at 6 am. Twenty minutes into the drive to VIR then home north of Leesburg, VA, I'm at 74 mph, 3,000 RPM on US 20. I get a momentary blip of a power loss, followed by the engine warning and central warning lights. The lights go out and everything seems normal. I called my fellow Porschephile and he runs through the common faults: gas cap tight, age of battery, etc. We conclude it is a warning light error or a minor fuel or electrical problem. The momentary power loss and lights continue to occur randomly every 2 to 20 minutes. I noticed oil temp increased by ~10 degrees. Oil pressure remained at 5 bar. Passing through Columbia SC, I made the decision to get the engine checked at Hendrick Porsche in Charlotte, NC. Fifty yards from the dealer I stopped for a red traffic light. On releasing the clutch at 1100 RPM, the power was erratic and within half a second there was no power and all the warning lights came on. Just like the guy who wants to drink all night, look at pretty ladies, drive hard and skid into his coffin, I rolled downhill into Hendrick Porsche, and downhill right into the service bay. When I got out of the car there was a large pool of oil under the engine. I hoped it was just a seal or oil line. Forty minutes later a mechanic gave me the news: the oil dump and numerous timing codes indicated IMS bearing failure.
So, I am looking at rebuild, new long block, or sell the car as a "roller." A rebuild, assuming the damage allows a rebuild, might get done for about 15K (according to several reputable Porsche engine builders.) A long block from Vertex would cost about 20K and about another 2K for removal and installation. Taking the proceeds (estimated at 12-15K) from a roller and getting another 997.1 would take another 30-40K - and the engine would have to have an improved IMS bearing. I am not ready to be "Porcheless." I want my 997 back because I bought it new and it dominated endurance sports car racing from 2006 until lately (I give a begrudging salute to Corvette and hope Porsche becomes more competitive.) At this point, I am leaning to having the engine rebuilt. Hopefully it is not toast. On Saturday I will trailer the car home and work toward a decision on the way forward. Sorry for the lengthy post. I wanted to share my experience and I look forward to any input to help me with this unexpected crossroads.

 

Very sorry to hear about this and wish you the best in whatever route you decide.

 

Did it have the easily-replaced bearing or crack-the-case bearing? What was your build date? What was your engine serial number?

Any signs of bore scoring? (Not to "pile on" - just collecting data to guide my future actions.)

 

Sounds like bad assumptions based on inadequate research.
So sorry to hear about the failure.
However, the conclusion is also flawed; only engines with the smaller bearing should go to the trouble of replacing it. Most 997’s have the larger bearing that requires splitting the case to replace. Lower risk, higher effort and cost to address.

 

So sorry to hear about this. When I bought my car 4 years ago with 72k miles ( Base 2005 C2 ) I did replace the IMS bearing along with a few other maintenance items (motor mounts, belts, etc)
Mine does have the smaller serviceable bearing! Now at 104k miles, I change my oil religiously every 4k miles with hopes of keeping fresh oil lubricating its internals as best as it could.
I intend to drive it to the ground and rebuild the motor if it did ever fail as I wouldn't be able to buy a car that's comparable for what I paid for mine + cost of engine rebuild.

Good luck with which ever direction you decide to go.

 

As others have alluded to I think some misinformation may have contributed to this.
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• Later 996 and early 2005 997: replaceable small single bearing with a high(ish) failure rate
• Late 2005 through 2008 997: non-replaceable large single bearing with a low failure rate (not replaceable without splitting the case)

So it's not that the 997 is largely immune to IMSB failure, but that 997's with the larger bearing are. Since the OP has a 2005 and stated he was considering replacing the bearing at the last clutch job it implies he has the smaller bearing. Not certain of course, but it would be good to confirm this.

To the OP sorry this happened but hopefully you can turn it into an opportunity. If you are a DIY guy consider a rebuild using relined Nickie cylinders and new pistons from LN Engineering with headwork from Hoffmann. There are some great DIY threads over in the 996 forum documenting the process, including displacement increase. If you can control the impulse to replace everything, you'll end up with a near-bulletproof engine for under $15k.

 

Ouch!! Sorry to hear this. I appreciate you sharing how it all unfolded. I don’t know if it’ll help someone prevent a total catastrophe in the future or just increase paranoia. I do hope you keep us updated as to what the damage is, your decisions moving forward and the rebuild or replacement, whatever course you decide to take. Best of luck.

 

Ouch. Sorry to hear, glad you’re going to figure out best approach to stay in the 911.

 

Sorry to pile on as well but are you saying you endurance raced this car since 2006?
If so, that would be quite a few track days. After years of tracking, I would assume my motor would need a rebuild at some point regardless of IMS or whatever with 100k miles and 15 or so years of endurance track use.

 

Sorry to hear. The good news is that you received 15 plus years of enjoyment from your 997. So it doesn't really owe you much at this point. A rebuild at this point into a 4.0, although costly at $20-30k, is not as terrible for you as opposed to someone who did not buy new or have many years /miles of enjoyment. Assuming body and all esle in good shape -what else are you going to get for that money? Also, look at all the cars on Barret and Mecum that are restored, retromodded, hot rodded etc - the $ that go into them -done out of love and enjoyment not necessarily return on investments. Bad news is the wait time if you go with FSI, or finding someone equally as 'competent' to do the rebuild.

 

Is your 997S engine an early 05 engine with the smaller more problematic IMS Bearing??
What is the engine number stamp??
Here is the engine number cutoff for the early Bearing:
Engine (3.8) number up to M97/01 68509790 has the older more problematic IMS bearing
Engine number from M97/01 68509791 forward has the larger revised IMS Bearing

 

On a positive note your car picked a good time for this to happen. With the price of these cars recently a rebuild makes sense. Putting $22,000 into a car worth $45,000 is not as painful as putting $22,000 into a car worth $19,000.

 

To clarify - the reference to endurance racing was to the 997RSR campaigned by the factory and the Flying Lizard team; not my car. I should have stated specifically that.

 

Thanks Sporty! Reading your words helped to reinforce some of the rationale that went through my mind. It is a great car. I will rebuild and drive on.

 

I'll let you know after I trailer the car home on Saturday.