The newest addition to the SCM Fleet is a 2005 Porsche 911 C4S, VIN WP0AA29935S620075, Engine #M96/0366500527. I paid $32,550 for the car, fully loaded with Tiptronic. The car has 72,000 pampered (or at least what look like pampered) miles.
However, there are no records of any maintenance done to the IMS bearing.
I’m not a Porsche expert, but SCM Porsche guru Jim Schrager is very direct about it: “I upgrade the IMS bearing on every relevant 911 that I own. When the bearing fails, it takes out your engine. Period. And all the black magic tricks of looking at your oil filter for metal filings are simply ways to let you know your IMS is going to fail.”
The subject of a class-action suit against Porsche, the IMS bearing supports the intermediate shaft in the engine. For more detailed information, go to LN Engineering, the widely known expert in such matters.
There is a lot of discussion about both single row and double row bearings, and the various failure rates for each. Then there is the question of whether my IMS bearing could be one of the non-serviceable units that requires disassembly of the engine.
I will, of course, be handing the car to Avant-Garde Collection here in Portland (owned by Matt Crandall, power-seller 911r on Bring a Trailer) for inspection before I make any decision.
I’m sure amongst the SCM faithful there are more than a few of you who have experienced this situation. If you owned this car, what would you do?
Can you tell from a visual inspection if the IMS has been repaired? Should I just go ahead and “invest” in the upgrade? Which repair would you use? What price range should this fall into?
Or should I go against all advice and take the chance that this is one of the cars that will not experience a failure?
I look forward to your thoughts in the comments below.
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13 responses to “Keith’s Blog: Playing Stuttgart Roulette”
I would have never bought the car without service history and the IMS bearing replacement! Was the purchase price so low that the IMS replacement was factored in?
IMS must be replaced!
Isn’t this car also subject to bore scoring?
Unless your guru comes up with information otherwise, you have already defacto made the decision to replace the bearing when you bought the car. If you sell it without the fix or knowing the status of the bearing the buyer will or should ask for the corresponding discount. Pay me now or later.
I would definitely do the IMS upgrade for peace of mind and potentially peace of wallet. I remember years ago stressing over the potential IMS failure in my purchased new ’05 Boxster S. I finally told Matrix to go ahead and do the upgrade. As is so often with Porsche, once disassembled, mine had the later 2006-2007 bearing with a negligible rate of failure. At least I got a new clutch and pressure plate given it was apart.
If it were my car I’d be really tempted to just drive the car. I bought a 2002 Boxster S with similar miles that I drove problem free another 50k. I only changed it as a “while you are there” when the car finally needed a new clutch. While potentially disastrous, my shop owner convinced me the chances were negligible with the mileage already covered in the car and that the odds of it happening to me in his experience was roughly equal to that of me winning a lottery drawing. It’s a personal choice, but for me I’m glad I made the one to not immediately change it. To each their own, but I would just drive and enjoy. I also won’t avoid going outside to limit my chances of being hit by lightning……. Good luck Keith!
My guess is that this one is going to be a long-term keeper, Keith. So just bite the bullet and pay the money to have the IMS replaced. You bought it pretty cheaply, but there’s one more payment due.
This car will
Likely see a fair bit of use, and I suspect you’ll be making a lot of great trips in this car. It will be the source of many great memories for your kids.
Nice looking C4S! One of the best 996s. Await advice from AG; I’d be tempted to just drive it. Over 72K miles already … Enjoy!
There’s a few schools of thought on this seriously overblown topic (failure rate is in the single digits). If you do in fact have the original IMS, if it were going to fail it very likely would have done so by now so save your money. On the other end of the spectrum are those that see it as relatively cheap insurance (a few grand vs. a $30k engine rebuild). Unfortunately it’s not always a silver bullet fix ; when I bought my 996, one attractive thing was that the IMS, RMS, and clutch (while you’re in there) had just been done. Unfortunately for the previous owner, he has just done the IMS a few years before and it was showing signs of failure (seepage). My advice would be to make your decision based on the results of 911r’s (Matt’s) inspection and expert recommendation.
Great advice above, I would have written the same advice.
You have a good source of advice on your fingertips with Matt.
I’ve watched the way you get your “new” used cars brought up to spec over the years so I suspect you will end up putting in the LN bearing. I would for the price.
That said, I’ve been in PCA for 54 years and know about a Zillion people that have bought M96/97 engined Porsches and only know of one that had the IMS failure. And that was on one of the famous “super low mileage” cars that sat in a garage most of its life.
If you listen to all the crap, you read on internet forums all used Porsches will blow up the minute you drive them away. There are two used Porsches in my garage now. A 991.1 with 76k miles and a 2021 Macan GTS with 40k. I change oil at 5000 miles, and follow the maintenance schedule by the book. The only non-scheduled maintenance for these two was a washer pump for the 991. I never had any “surprises” with any of the Porsches, new or used, that I’ve had over the last 55 years.
I would do it absolutely. No question. There’s nothing more expensive (or depressing) than regret and peace of mind is worth its weight in gold
The more I read stuff like this, the more I believe that the absence of comprehensive service histories should be more severely punished by reduced prices for cars without them. I am by nature a squirrel, saving every little bit of paper that comes my way. But when we’re talking about distinctive vehicles decades old, I can’t imagine why any responsible caretaker wouldn’t keep receipts from shops. Buy a damn file folder, pal, and stick those service records in it. Or if your shop sends electronic ones, put ’em on a flash drive and digitize the old hard copies. I don’t fault original owners who bought the cars new and drove them as one does new cars, but ten years or so after, as the mileage gets into the range where “things happen” and “things need to be replaced,” let’s keep track of what those are. Barn finds may be different, but for driven collectables, let’s treat those without fat loose-leaf books with scorn and shame owners into getting more serious about this. It’s not that hard.
Porsche aficianados are amazing — the auto company that is the pinnacle of advanced Teutonic engineering produces a car with a major flaw that costs each owner tens of thousands of dollars (out of warranty, no less), and they lose no sales or any degradation of their customer fan base. It’s almost like a cult. I know that if I bought a 911 that had the potential for IMS failure or had suffered an IMS failure, I would never go near that brand ever again.
Glenn in Brooklyn, NY
Basically, my understanding is that the early IMS bearings are not that bad to replace, and you should do that every 30,000 miles or so… then no real issues. If that’s the case, replace the bearing.
The good news is that the later, sealed bearings, which you are unlikely to have, while much more difficult to replace, also are much more reliable and shouldn’t be an issue.
And, finally, yes, bore scoring can be an issue on these cars. You just need to close your eyes and hope on that one.
Personally, I skipped all these issues by buying a 996 Turbo instead, which has (as you know) a completely different motor.