'04 C4S - what's up with this? (IMS bearing puzzle)

I know there is an IMS bearing thread. It's about 400+ posts. It's late, I'm old, so I figured I'd beg for mercy and just submit a puzzle to see if anyone has an answer.. I'm looking at an '04 C4S, it has a number of things that ring my chimes: Tiptronic (remember I'm old, the joy of shifting left with arthritis in my hip and knee a new top and new Alcantara headliner - within the past year. HID/Lintronic lights, a replacement for the MID-2 that it probably came with (Pioneer, I wasn't impressed but also hadn't read the manual) and a few grand of upgraded amp and speakers. It's also a color I liked (dark blue, gray interior, and new gray top), with the top up - there was no squeaking/rattling which what made me hate my M3 convertibles. It had about $6k of carbon-fiber scattered around the interior and Alcantara in various places that had been leather. The carbon fiber was a tiny bit overboard, but that can be remedied. And the price is OK. Thing is - the salesperson at the dealership got the service records for the past few years for the car. It appears that back in 2015, mileage not exactly known, it suffered an IMS bearing problem - and the dealer replaced it. The invoice doesn't show a Porsche part# for the bearing. It shows an LN-Engineering part number for their bearing replacement kit - 106-08-13. I just have to guess this is the bearing and a borrowed installation tool kit. So they did that, replaced the water pump and oil cooler assembly, and oil filter, the ATF cooler, an O-ring and while they were at it - a wheel bearing. Cost about $7,000. Things seemed to be OK for about 16 months, then in 2016, at 65,657 miles - something major melted down. The repair consisted of removing the engine, "remove cylinders" (heads?) codes for misfire on Cyl 4-5. "Found poor valve seating, worn." They replaced All the timing chain bits, tensioners, guide rails, timing chain, ALL intake valve lifters, ALL fuel injectors, and about 80 other miscellaneous parts, mostly related to the heads. The total costs for this and the prior work was $14,947. The miles between the two was 15,718, for a cost per mile driven of $0.95 (this is actually all broken down on the work summary.) Since then - it seemed to be running fine. No more repair orders for engine stuff. Usual brakes, suspension stuff. It was running fine when I drove it today and was almost impressive (although the Tiptronic isn't near as good as the 8 speed on my Cayenne Turbo) - but it was a fun drive once the tires got round again and the RPMs got over 4K, and the jughandle got REAL TIGHT REAL FAST. Went through it like a champ. My question is - what do you think happened there? The had the bearing go out, replaced it maybe with the LN replacement (the full "kit" was $350), then other stuff that was stressed by the bearing failure finally crapped out a year and sometime later? It could be a good thing - if everything was fixed finally since the last time the engine was apart. It's been over 20,000 miles since then, and the engine wasn't making weird noises that I could determine (but I didn't bring my mechanic's stethoscope, and I'm old - and a bit deaf..) Any thoughts on this? I'm looking for a toy.. this wouldn't be a daily driver, but if the engine is going to blow up again, I might just pass on it. I wonder if I can get them to drain a sample of oil to send overnight to Blackstone? That might tell me a lot... Any comments, razzing, whatever is welcome. I've decided the time is right for a new toy (the last one was a '01 BMW M-Coupe.. stick of course since they came no other way..) and since my Cayenne has crossed the 100k mark, it just seems to be chugging along reliably so I need a new obsession. Help a brother out here..

I view it as 2 unrelated engine issues that happened some time apart from each other. They both were correctly repaired and are common issues with these cars. I would see it as a good thing since you know those issue have been taken care of. If its been 20k miles since then i wouldnt even be thinking about those issues any more. Some people will point out that the IMS (depending on which was installed) still have a service life. Unless an IMS Solution was installed. If it was just a replacement bearing it only has a few more years of life before its recomended to replace it again. Prepare yourself for a major argument on this forum about the IMS issue

I would try to talk to the dealer who changed the IMSB. Asked them what does "an IMS bearing problem" mean. Was it a Porsche dealer? Is the car at a Porsche dealer now? If the IMSB shredded itself and puked stuff into the engine the latest repairs could be a secondary failure due to the IMSB failure. If so, there could be other hidden hand grenades in the engine. Yes, there will be numerous opinions on this possibility. Do some more checking. Oh and never apologize for being "experienced"!

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I'll try to keep my comments short and sweet... here goes the play-by-play The Porsche dealership recognized the car was experiencing IMS bearing failure. Instead of properly replacing or rebuilding the engine, they instead, decided to install a new LN Engineering bearing into a failed engine that was more than likely contaminated with shredded metal from the original OEM bearing. This at the tune of $7,000. After a short period of time, the metal that was trapped and spread throughout the engine started to play havoc on the internal parts which caused another failure at the tune of $15,000. Again, instead of properly rebuilding the engine from ground up, the dealership decided to just replace parts that were identified as damaged. For the owner ... Fool me once, shame on you. Fool me twice, shame on me! In conclusion, my question to YOU is... do YOU want to be the "Fool me three times" guy???

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Oh no you "dinna"! Now you started it! Buckle up...it's going to get interesting. BTW your assessment is exactly what I was "suggesting" in my post above.

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No, this probably won't show a true picture. You need trend data from all oil changes over the last 5 years especially after the LN bearing was installed. More than likely, the current seller has changed the oil just prior to putting it on the market.

Who did the bearing replacement? The condition of the original bearing is crucial IMHO. Get the serial #of the replacement to LN and see if they received the old bearing. That could tell you a lot...

I struggle to agree with the others above. The OP said the first was an IMSB issue and the second was a valve seat issue. I would suspect the dealer suggested the chains and guides as they are not uncommon to fail. If the head had to come off it would be smart to suggest chains and guides while they are off anyway. Thoses 2 are not related. Also the time frame between the first and second repair was 15k miles. Now another 20k miles has elapsed. Either way the only way to know would to either be the prior owner or the tech who worked on it. We all are looking at this from different angles with limited info. All great opinions. But they are just that.

^^Agreed!

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While I agree with you that all of the above are just opinions. I also agree OP needs to get info direct from the source, if possible. I don't necessarily agree that it is "normal" for these engines have valve sealing issues at 65,657 miles without some abnormal contributing factor. That "factor" could also have wounded other parts internal to the engine and that damage may not reveal itself immediately. I'm no engine expert on these cars but do understand engines from hobbies and work experiences.

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I view the two occurrences as connected. Something serious went wrong with the engine. I don't see bent values, damaged timing chains, and other head damage at 65K miles as "common". Chain guides? Fuel injectors? Yes, common wear items, but NOT chains, tensioners, lifters and some "80 other miscellaneous parts related to the heads" at 65K miles. Not common wear items in my book. Just my 2 cents. Something caused some serious stress on this engine. In order to properly change out the timing chains, you'd have to completely open of the engine down to the crank shaft carrier assembly, correct? Seems like at least a partial rebuild. Therefore, if I was the owner of this car, I would have had a shop completely rebuild this engine with nikasil bores, better pistons, connecting rods, IMS Solution, etc. If a Porsche dealership definitely did this work, then they would've reassembled it will all the known items that are prone to failure. Hint - cylinder bore scoring (shhhh... I didn't say it)

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Exactly! And, we have to bear in mind that the owner of this car dumped $22,000 into this car at around 65K miles and within a 14 month period. That's not normal, ((coughs)) but we're talking about the M96 engine here and so maybe it is?.

Again, i agree with all the opinions and disagree with them just the same. I have been a mechanic for 23 years. I have torn engines apart with only a few hundred miles and found problems that should never occured. I have seen cars come in the shop with one major problem, fix them, then they come back the next week with another completely unrelated issue. Good luck explaining that to the customer. And i am not saying that it is normal for a 60k mile car to have chains guides head work and injectors. But as a tech i can easily see this as 2 unrelated issues. If an injector was stuck open flooding a cylinder it could easily burn a valve or valve seat. That would explain pulling a head for repairs. Then if they found a guide issue while tearing it down it would be "common" for a shop to recomend all the timing componets (chains, guides, tensioners). Decisions and recomendation come down to whats is best for the repair. Not always the cheapest repair. We recently had an F150 come in the shows missfiring on all cylinders. It was quickly and easily diaged as a broken timing chain guide caused by a failimg tensioner. Some shops would have just put a guide and tensioner. The bigger picture was the truck had 250k miles and had been poorly maintained. Our recomendation was to replace the chains, guides, tensioners and both VVT phasers. These are all common failure items and it makes no sense to replace just the broken parts and not the rest. Again, we are all either right, wrong or not even on the same page of what really happened. Just not enough pieces of the puzzle available. It's too bad the OP can't get a hold of the previous owner and ask questions.

OP here... I'm attempting to get hold of the previous owner. The repair order has his name and address, but no phone number. Found him on FB and sent him a message asking if he'd get in touch with me. No response yet. The analysis' of everyone are quite interesting. My thought was that since this work was done at around 65,000 miles and the car now has 88,000 miles - probably the engine is OK. I have service receipts for up to current date - and nothing engine (or driveline) related is listed. The receipts I have are not in a Porsche format.. at least none I've seen. It's the selling Porsche dealer who provided them to me so my WAG is - the work was done in their shop. I'm hoping Monday morning to find out a bit more - and perhaps talk to someone in the service department who could fill me in on what was done if it was done there. After reading: https://rennlist.com/forums/996-foru...30k-miles.html (as people noted - a sensationalist title) - that discussion really makes me consider if I want an 996 at all. It is interesting that most of the subsequent work - new top, carbon-fiber stuff up the wazoo, new audio - all was done after the engine work was completed. Then it suddenly seems to have gone up for sale Did he get a bad Blackstone report or was he just looking for new(er.). BTW - I didn't think it worth mentioning, but apparently, around 03/13/18 it suffered damage to the front left suspension. Two control arms needed replacing. I can imagine that sort of damage that time of year in NJ being pothole related. Thanks MUCH for all the great responses!

Take most of what you hear on forums with a grain of salt. Typically most forums are full of problems. The forum is called " technical discussions". Like any other car, the 996 has its issues. I have had my 996 for over a year. I have had no actual issues other than a radiator that started to leak and a drivers door actuator that failed. I did go to town on all the maintenance items. Dont let the forum make you think they are bad cars. They are fantastic to drive. Driving a 911 is like driving no other car. Every time i drive mine its like the first day i got it. I currently am 100 miles away from my home on a drive. Every mile was with a smile. Next month will be my first to go to a PCA event at Roebling Road. My face will most likely be stuck in a constant smile for a week.

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As Mbren said above the 996 is NOT a bad car. They do have their issues that can get very pricey very quickly. I love my 2005 C4S which I purchased in 2014 with @52k miles with absolutely zero knowledge about Porsches what-so-ever. I've only had a few minor issues, but don't drive it too much. It is currently getting a rebuilt engine by the best engine builder in the nation, in my humble opinion, due to scored liners which is one of the weak points of the engine. I would encourage you to find as much about the car as you can. They are a performance sports car and do need maintenance that a Camry does not. Do some reading here and other sites to educate yourself. Knowledge is power. Only you can evaluate if you wish to buy one. They are an intoxicating car to drive...

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See...even though we all may have different approaches to the potential problem. we all agree in the end. I 100% agree with Wildbilly. I am subscribed to his rebuild thread and would hate to be in his shoes. Couldn't agree more about his builder. This is a forum of people getting together to help each other. Research Research Research.

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106-08-13 is the IMS Pro Tool Kit, not a bearing. https://lnengineering.com/products/i...-retrofit.html

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I realized that. The kit costs less than the amount listed on the parts list. The bearing itself costs more. My WAG - the owner provided the bearing (which is rather expensive), and the shop bought the installation kit and tacked on some profit for themselves. There is other evidence of the owner providing parts for some of the jobs which I assume he bought from some of our fine vendors (Vertex was one he used.) That also makes me think that the receipts I have are not from a Porsche dealer - instead from an independent shop. That could be good or could be bad. Doesn't matter at this point. The alure of this car is fading - perhaps due to a wish not to deal with these sort of engineering flaws. BTDT with the Cayennes.. finally have one with all the engineering errors fixed, only took 100,000 miles to do it. I think I'll go back to looking for a 987.2 - they're looking more and more attractive to me. The 2009-2012 appear to be pretty bulletproof.. at least for the use I'll put it to (track days aren't on the schedule.) Thanks for all the input! I think I'll go back to lurking in the 5 different forums covering Boxsters and Caymans (something I will move to straighten out if I get one, since I'll be hanging out there..) Thanks again!

There are plenty of used 996s for sale. Why buy one w/ yellow flags?

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True.. I think that moves most of the 996's out of my market interest. Reading the several voluminous threads here about bore scoring and IMSB failures - it sounds like a "when" issue, not an "if" issue. There may be some good IMSB fixes out there, but even the vendors of those fixes seem to imply that none of them can be considered to making it a "never happen" sort of thing. I can't really afford the post-IMSB 911's, so it's back to looking at 987.2's. BTW - is bore scoring known to happen in 2009 and newer 996's? Starting early 2010 Porsche changed the process on prepping the cylinder bore on the Cayenne/Panamera engines. Engines made since that time - well - none that I know of have suffered a bore failure.