I'm buying a 1999 911 Carrera, reading mixed messages about my IMS. Do I need it?

Hello, I'm buying a 35k mile, 1 owner 1999 911 Carrera. Original owner said he's never done the IMS, I'm being told it has the more robust IMS since it's a 1999 but then others are telling me they have personally had friends blow up their engines that had 1999 cars. Do I need to do an IMS retrofit on the car?

https://rennlist.com/forums/996-foru...his-first.html

Here for the comments.

Yes and no. Yes you have a more robust bearing but it can still fail... so the prudent choice is to just change it. If you let it ride you could be ok or you could grenade your engine hence the prudent choice of just doing it as there�s no rhyme or reason behind if/when it goes

This is going to depend on your personal risk tolerance. If you think the worry will affect your ability to enjoy the car, go and get a retrofit or even better, a solution.

Mine replaced at 87k by p.o., still have original - perfect condition. i guess you will never really know 'til you get in there. 1999 had so few problems they were not part of the class action suit.

What always sounded like good advice to me was, if the engine is out for a clutch or RMS R&R, you might as well have the IMSB replaced. Otherwise, no, leave it in there. Crossing my fingers...over 8,000 mile in my first year, on 80K+ engine/car, so far, so good. Check oil filter for metal at oil changes is a good practice.

The short answer is, yes, you should change your dual row IMS bearing. When I did the clutch/PP/TO bearing on my 1999 Boxster, I changed the IMS bearing to a Vertex cylindrical roller bearing with five times the radial load capacity of the dual row ball bearing. Upon inspection, the original dual row ball bearing was loose and clearly on its way out, although in my case the car had 77K miles. You've probably got a margin for error with only 35K miles, just be aware that the dual row bearings do fail, and that a clutch change is the perfect time to renew it. Best of luck.

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Cooler, Look, it's like this... either you believe the IMS bearing is wear component or you think it should be left alone. In my opinion, when you go to change out the clutch kit, replace the bearing. That way you can enjoy the car with a fresh bearing in the car. If you don't won't to ever worry about it again, then install the IMS Solution from LN Engineering. You car is 21 years old now. Parts age and need replacement even if you have a low miles car. Unfortunately with this part, when it fails it takes the whole engine with it.

Just have the IMS Solution installed and never worry about it again!

Thanks everyone. Looks like I'll do the IMS when it's time for the clutch on the car so I'm thinking at 50-60k miles probably. For now it's being PPIed today and if it passes with flying colors I'll buy it, drive it home and enjoy driving this 1 owner 35k mile beauty.

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Wise choice. Just keep a close eye on ferromagnetic metal in the filter. You may want to drop the sump plate and examine too. Remember to also use an oil that has a good anti-wear additive package - look for good value of ZDDP and Moly.

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Appreciate the advice, what oil do you recommend? So I can ask my mechanic to purchase that for oil changes.

I fought the hype. I own a few P cars and one is a low mile, mint, better than new 2004 996 AE I knew when I bought it 8 years ago now that the 996 is a POS, IMSB failure prone, especially on low miles cars (regardless of annual oil change and BS lab test) 10% chance of a 25k engine rebuild etc.... 1999 cars better blah blah blah Aftermarket parts sellers and fear mongering FlatSix engine builders promoting horror stories and ginning up replacing parts before worn.... 9-10 cars dont have cat failure but few stories about the many 996 going without major repairs bills. Their owners are not on RL and happily just drive the DD 996s Now, I will admit, every time I started my 996 I was thinking is this the day. Boldy saying to myself Jake will build me a Bad A__ 4.0L if she goes. So warm it up and drive it like you stoled it or are a flipper! Who cares its only money, and maybe your marriage but what the heck. So, after 8 years of ownership and the advent of the IMSS I had bought into the hype and paid the bill. Now, the dreams of a 4.0L are gone but so are the little voices saying Jake could be right. My mint, better than new AE could be the one. Dont risk it. Also gone are the nagging little voices and darting eyes ever watching the check engine light section of the dash and listening for odd noises ready to shut her down and call the flat bed for the long ride to Georgia.

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It's a 20 year old mechanical part that if it fails will render your car nearly worthless. I just had my second IMSB replacement (double row) in the ten years I've owned the car. My car has only 75k miles on the clock. Both old bearings were in perfect condition. Do I regret spending the money? Not for a second. I'm also having the UAOS installed as well as chain guides and new chains as preventive maintenance. I want to enjoy the car and not have to worry about it.

Low mileage cars tend to have more IMSB issues than higher mileage cars. Another big concern for you should be bore scoring. Get a thorough PPI

There is a very good article in the Excellence Buyer's Guide 2020-2021 regarding IMSB failure, replacement, and advice about how to think about this issue when purchasing or owning a Porsche 996. /X3

Perhaps you should do a quick browse of this thread https://rennlist.com/forums/996-foru...e-failure.html The problem with IMSB failure is that a PPI won't pick it up unless it's way far gone already (stage 3 - ie. it's making nasty noises). There are also other modes of failure that a PPI will give you a false sense of security about as well, so be careful. If I were you I'd figure the price of the IMS bearing replacement into the cost of the car and see if it still makes sense. Better yet, just add $5k to the purchase price and have everything addressed once/if you get it (this is not to say don't bother doing the PPI - they will pick up obvious stuff - which could save you a bundle in the long run). Good Luck

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Driven DT40 -5W40 A40 approved MOTUL 8100 Xcess 5W40 Liqui MOLY 5W40

I believe my 99 has the original IMSB at 65,000 miles now. I plan to leave it until clutch time. At the point, I�ll be doing UAOS, RMS, IMSB and clutch kit.

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+1!!

Do the IMSB, leave the IMS alone.

I've investigated the IMS bearing thoroughly, read from post #492: https://rennlist.com/forums/996-foru...-first-35.html In short: Do inspect it but only replace it if it shows any signs of wear or damage. And replace with the same type part. The aftermarket bearings is not needed and is not as proven/reliable as the original design.

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That makes about as much sense as spending $15,000 on a complete engine rebuild and re-using the main bearings because they have plenty of life left in them. Well, that�s up to you of course. You might be right (and everyone else could be wrong), but it�s not the sensible thing to do.

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Read from post #492.

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I did read. If you are happy with your "slide rule" analysis then go ahead and leave your bearing in place. I wish you good luck.

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Can you technically explain then what's wrong with my 'slide rule' analysis. Because no one have yet so far.....

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I hadn�t seen that, thanks for sharing. I do agree that too often, no good deed goes unpunished. There is a case to be made that messing with a perfectly good dual-row bearing by installing a new bearing that could be defective, or a perfectly good bearing that is installed incorrectly would be worse than just leaving it alone. I continue to read posts where folks are tearing into their cars to try to proactively address some issue, and many times, the issue morphs, or remains, and then bigger problems sometimes follow. Sometimes those seemingly small but stubborn issues are just symptoms of a bigger issue that ultimately leads to engine failure. I may have forgotten that one could inspect a dual-row IMSB, but my logic in going to replace it anyway still stands as a good approach when we are already in there for another reason. It remains to be re-stated that finding a great shop that has 996/997 expertise in high volume (not a 911 air-cooled expert shop, because I�ve been to shops like that, and many of those folks still become flustered with the 996 quirks) is paramount. A simple as these cars are under the hood, lack of true expertise is risky and costly. My main reasons to replace a dual-row bearing while we are in there are: 1.) A very large chunk of owner�s time and money will be spent on just getting to the bearing. The value proposition of a new bearing is higher at this point. 2.) A car with a replaced bearing is more desirable on the market. That could change if there ends up being some strange benefit of the originality of a stock IMSB, Lol, but that would be a strange thing indeed. 3.) It may give peace of mind to the owner. Sleeping well at night has massive value, physical, mental, and monetary. In the end, you may be correct, but there is value on sticking with consensus, since nobody knows 100% why these bearing fail.

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No. I just wish you well with your decision. To each their own...