ISMB Replacement at 185k?

For the past few weeks I've been vetting a car (2000 Carerra) with very high mileage (185k mi). The owner of the car replied to my questions about ISMB by informing me that the clutch, RMS, and IMSB had been done prior to their ownership at about 130k mi (their ownership began in 2011). They also informed me that they had records to detail this work and that they would provide them when they returned from a work trip (last Friday). In the meantime, I had called several area Porsche specialists and determined the rough repair history of the car for the past 3 years including the car's current shop (who told me it was in perfect order and detailed a relatively rigorous repair history) and the shop used between the car's purchase in 2012 and the current ship (who told me they noticed some misting around the RMS area). 65k is plenty long enough to warrant a clutch replacement, so I intend to use the cost of clutch, RMS, and IMSB to talk the owner down $3500. Meanwhile, on Friday I got some pictures snapped of the repair history, specifically the invoice for the clutch job they had referred to (and a picture of a 2in thick stack of paperwork, so at the very least the car is well documented). Unfortunately what I saw on the invoice was: Clutch RMS Pilot Bearing Which set of a whole series of alarms in my head because pilot bearing≠intermediate shaft bearing. It was also done in 2008 with 110k and the bill came to $1575, which does not equate to IMSB either. So, two questions: Do you agree that I should believe IMSB was not done at this service? and perhaps more importantly, If this car has indeed gone 185k mi on the stock IMSB, it would lead me to believe that the IMS and other contributing factors described in this thread are not present in this car. Do I mess with it and do the IMS Solution or do I leave it be and just do clutch and RMS?

Not done=do it with the other items on your list.

First double check. Maybe the IMS was done at 130k as a separate thing and not at 110K with the clutch 2 - and here is where theories fly. Causes of IMS failure include but are not limited to: wearing out, improper lubrication, and for lack of better words - improper tolerances (from the factory). I think with so many miles on the motor you can rule out tolerances - you got a good one - so I would replace it, but don't know if you need to go all the way to a solution.

Since you are planning to replace it anyway, why do you care if it was previously done? Just do it with the clutch work and don't look back would be my advice.

With that many miles on the engine, all I would do is routine maintenance and plan for an eventual engine rebuild in the future. Could be at 195k or 380k miles - nobody knows - but the point is, you are getting up there and things just wear out regardless of IMSB. Also, don't assume the clutch will or will not last another 50k miles. I think it's smart to negotiate based on wear items, but proactively replacing the clutch unless you believe it to be worn is, again, not something I would do. The original clutch on my 88 failed in 2005 (115k miles)

The DMF may alo be an issue at these miles . As others have wisely said - just maintain it and expect to need a rebuilt engine at any time. Most of us should think that way - regardless of miles ! There is no reliable way to predict the future repair costs of these M96 engines -young or old. If it was a Toyota -different story. If you can't/won't allocate $15k for an unpredictable rebuild project ,find one with a cast-iron warranty -in my very expensive experience. If you are going to dump lots of money in an old car, you need to love it or be convinced it will appreciate. Maybe consider a Mezger engined Porsche or a later DFI

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I guess that's what I'm getting at. I have two choices, do preventative maintenance now to the tune of $3-5k or wait until something breaks. If it's the clutch, then not a big deal, if it's the IMSB, then it's a rebuild or new engine, and if it's something else... then chances are it'll need a rebuild. My hope is to buy it, drive it for 3-5 summers, and sell it when it hits 200k. I suspect I'll need to do brakes three times in that time-frame, tires twice, clutch once when it fails, and oil once a year every 3-5k. I am not planning for a rebuild in that time frame, but per the advice I've gotten here it's a potential outcome I'll need to accept if I'm going to move forward.

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The question here is, do I just have the bearing replaced, do I do a retrofit, or do I do the IMS solution? The latter seems to be the logical choice, but it requires finding one of the rare certified installers, bringing the car to them, and having it installed for more than twice the cost of the retrofit (I can't tell if $1200 is parts alone or includes installation). Step 1 is going to be a magnetic drain plug, so potentially I can catch any emerging issues... with that said, how much help is it if the IMSB can go from 0 to failure in 500-800 miles. I'm not going to change my oil that frequently... Honestly with all of this advice I keep coming back to the position of... if I buy the car it's a gamble. There is no way to know the engine won't grenade or the IMSB won't fail. The truth is the IMSBs on these engines have a 1% failure rate, which is still high but after 185k, the chances are it would have happened already if it's going to. I'll probably have to decide what to do in terms of IMSB when I do the clutch, because I'll be there anyway. Then I'll decide between a factory bearing and $600 retrofit (since IMS Solution is cost and time-prohibitive). It's a gamble... and I'll have to know that if I buy the car there is a 1-2% chance it could fail at any moment. The question seems to be can I live with that risk.

You want to change the brakes 3 times and the tires twice in 15k miles? Are you planning on using this car 100% of the time on a track?

How much are they asking for this HIGH mileage 996? 3-5 years, what do you think you get for it then? I'd look for another lower mileage car if it's more then $12K. There are hundreds of them out there... Don't forget, you can buy a used motor for $7Kish. The little things on a car with that mileage could end up costing you a lot more then you think.

And do you really consider 1% risk high in any endeavor or just in automotive terms?

What 808Bill said - what is the asking price? If it is $12k or less, you don't proactively fix anything. You do routine, preventative maintenance and fix something when it breaks. Don't get confused by the guys who are spending $25k to $30k on a low mileage car. That logic just doesn't work with a $10k or $12k car. Remember, that car is worth $6k as a roller. So if you are paying $10k for the car, your risk is $4,000. You can spend that much on a clutch, IMSB and all of the other WYAIT items. So, you are going to spend $4,000 now to avoid a potential $4,000 loss later. You might drive that thing for 5 years and put 40,000 miles on it and pass it on to the next guy without it ever needing a clutch all the while selling it for the same $10,000 you paid for it.

Either spend more and find a lower mileage car, or buy this one and just drive it and give it proper maintenance. Is something breaks...fix it...but just drive it.

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+1 ... You do your math like I do !! Step 1.Just buy the car..Step 2.drive it like Porsche is going to pay you $1mil to blow it up,Step 3. then if it breaks fix it and repeat Step 2 ....You will be happy !!

Asking price is $13500, I am planning to offer $10k, citing the cost of clutch, RMS, and ISMB replacement quoted to me by a local Porsche specialist. If they go or it or within $1k of my offer, I think I'll move forward, otherwise I'll move on. And I don't think I'll do that work now, just know that sooner or later the clutch may go and that's what I'll be in for.

If you get it between 10-12k, just change the fluids, get the magnetic plug, and maybe spin on adaptor, keep an eye on things, and drive the hell out of it. If you find that you fall in love with it (pretty likely!), THEN you can think about some other options. At that price, don't over think it. I'm a cautious person by nature, but sometimes you just gotta take the plunge.

The Solution is for low mileage cars, it doesn't make a lot of sense to put a $3.5-$5k job into a car that's already long in the tooth. If you take it to a certified installer they probably won't do the job given Jake's guidance on installs. You are running into the recommended mileage & age for a new retrofit bearing, so that's really a judgment call you need to make. If it was me with that car @ $10-11k purchase price, I'd have the cylinders examined before spending thousands on preventative maintenance. Reason being, if you have scoring or ovalling that has you close to a rebuild already, I'd rather save that money and set it aside for the rebuild. If you have no appetite for a rebuild, the cylinders are free of scoring and you want to see how far she'll go, maybe it makes sense to do a few things now & enjoy the car for a few years.

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$10k should buy that car.. and with 185k on original bearing... leave it alone unless you're going in to do the clutch. And even then, if you take the IMSB cover off and discover a perfectly fine, sealed bearing in there.... I'd probably lean towards leaving it alone. There's less than 1% chance of failure and most happened early in engine's mileage life. If the original bearing is still there at 185k, it's doing the job as Porsche intended it to.... Assuming you buy the car, here's what I'd do 1) Get oil sample mailing kit from lab (many here use Blackstone Labs) 2) Try to find out what oil was previously used. Consider switch to Gibbs DT-40 or other high-quality oil if you can't find out. 3) change oil. a) collect sample, send off for UOA b) install LN spin-on filter adapter (to eliminate the bypass w/old spring) c) install magnetic drain plug 2) Drive car, learn quirks, monitor oil levels and watch for oil from the exhaust, listen for chain rattle, and so on..... while you are waiting for UOA to come back. 3) Post UOA results along with your driving impressions here for analysis and discussion. Depending on UOA results, you may want to consider these additional tests if you see anything in the UOA showing excessive wear: a) Leakdown & compression tests b) Boroscope to see if scoring is an issue (assuming high oil use) 4) At that point you will be looking at one of the following: a) If you buy a good one from someone who hasn't neglected the car and your oil analysis doesn't hoist any red flags, you may be lucky and simply get away with an annual service plan based on your most immediate needs and standard PM items, say maybe $1,500-2000/yr~ish. b) Or, if you end up with a worn-out dud of a car (hope not) you are looking at an engine rebuild sooner than later, which will exceed $12-15k in cost and likely cause considerable re-evaluation of your desire to own the car. Ideally, this is more han a few years down the road for you... Many here acquired their cars in the 50~110k mile range, often without any service history (speaking for myself) and going with the full engine-out refresh for upwards of $5k (Clutch, RMS, AOS, T-stat, H20 pump, vario cam tensioners/pads, coolant reservoir, plugs/coils, tranny/engine mounts...)

Since ball bearings have a finite life, I would never take the position that "I'd probably lean towards leaving it alone". At 185K miles I would be replacing it sooner rather than later.

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Yeah, but everything has a finite life. So then the problem is everything that would eventually need to be replaced should be replaced when? I've heard plenty of stories about people doing all this preventative maintenance and then having engine failures. Leave sleeping dogs lie should be considered here, but balanced with replacing items that are worn out. If the goal is to get to 200k miles, I would just do routine maintenance and only repair what is absolutely necessary. Chances are that leaving a 185k miles IMSB alone to get to 200k miles is very doable by doing nothing but oil changes and oil filter inspection. If the car made it this far, it's a good one.

You guys are aware the IMSb in this car was replaced at 130k, right?

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And it's due to be changed again...I'd put my money towards a much lower mile example in the $15K range, they're out there.

At 185K I doubt that the engine would pass a pre- qualification for the IMSR procedure. I see that the threshold for passing is usually around 130K, beyond that cam deviations from worn wear pads, and stretched chains often get in the way first, then comes the compression/ leak down test and that will usually take them all out beyond 145K miles. Probably better to let this one go, and start saving pennies for an elective engine reconstruction.

Quotes source posts: 14101388, 14099961, 14102357, 14100741

Incorrect. I was told it was replaced at 130k by the previous owner, but the invoice (record of installation) definitely does not reflect that. It shows a pilot bearing replacement, but neither calls out ISMB directly nor does the price reflect ISMB replacement. Thanks, this is good information. I suspected it would pass based on making it 185k on, apparently, the original bearing. To me this appears strong evidence that the engine was without defect from the factory, I didn't know the prequal included wear factors as well. Good info, thanks! I had intended to boroscope (and maybe compression test) during PPI. The specialist I had intended to use may no longer be an option, however, since the owner is volunteering to drive the car to me vs. me driving to them (and the specialist I had lined up). So I'll have to ensure I have an inspector willing to do those things. Scoring is near the top of my list of things to check, due to the high mileage. If the owner doesn't come down below 11k, or if the car shows signs of needing an engine rebuild soon (scoring, for example), I am going to walk. It doesn't make sense to dump 17-20k into a 185k mile C2 when I can get a 90-110k C2 or even C4 for the same price.

Thats called luck. The car is a 2000, don't be concerned with bore scoring. The 3.4 engines didn't use the high silicon forged pistons that were used later, which add to the chances for bore scoring.3.6, 3.8 and 3.4 M97 (Cayman, not 996!) engines kill the bores all the time. The 2000 engine could lose a cylinder, but the chances are much slimmer. Be concerned with a cracked cylinder head, thats Y2K syndrome.

run. dont walk. run. suspension, transmission, at those miles, you'll be paying more sooner or later. unless its $8500 which it should be

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Gl with it, don't be shy about your price expectations. These cars can quickly become $20-30k 'investments' even if you buy in good condition with a healthy engine. Mine needed coil packs, plugs, AOS, oil cooler line, coolant line, etc within 10k miles of purchase. All standard parts refreshing due to age & wear. I'm happy to do those things & am under no illusion that work done last year will prevent repairs in the coming year. It's an ongoing process to keep them healthy & running strong. The plus side is there aren't many cars out there that can deliver the same fun for similar money!

The most expensive 996 you'll ever buy, is the cheapest one you can find.

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It seems I've heard this before... 👍

Apollo 911 is the exception 240k+ miles & still putting down 240rwhp or so