Edgy01

Sadly, the same engineering shortfalls have existed with Porsche for many years. If you've been around Porsche long enough you'll recall the dreaded chain tensioner issue that plagued the 911 from 1963 until 1984 when they finally figured that they needed to feed engine oil to them to keep them from seizing up. That's over 20 years of a shortfall!

At other times it was supplier shortfalls with soft valve guides. The litany goes on. No one wants to have to deal with an IMS issue but it's good to prepare yourself with the possibility.

Sometimes we are very demanding of engineering firms. We (as externals) see these weaknesses as gross engineering shortfalls yet you know that Porsche demands much more from their engines than most other car manufacturers. Let's not forget the incredible performance these engines are capable of, coupled with far above average fuel economy at the same time. Don't forget maintenance intervals--vastly extended. So, here we have incredible performance, great economy, and we have to do less to keep them performing at that level. But there will also be some that fail due to myriad issues that simply cannot be accounted for. My excessive oil consumption (to me, with my 997.1S engine) is possibly due to a tolerance stack that is working against my engine) is more of a nuisance than a costly failure. But it represents .LT. 10% of the 997.1 engines out there. Still, Porsche has no idea why it's happening.

The latest DI engines are still so new that their Achilles heels are unknown. I have long felt that Porsche does a very respectable job in testing their prototypes (to include engines, etc.) but that the real 'testing' is when you as a firm release these things to the masses. Only then will you ever discover what you forgot to account for. Untrained owner/operators can get things to break much sooner than a trained Porsche 'pilot' who is driving a car that is religiously maintained to factory specifications before it's returned to road testing. (In the military we used to say that the troops can break a solid steel ball).

I'm glad that you have a certified used car and that Porsche will have to resolve this on their dime. When you get your new engine drive it like you stole it. They like that the best!

DreamCarrera

Where did you come up with this figure?

Are you an in the know Porsche AG employee?

Spiffyjiff

i'm guessing the poll on this site which is currently at 6.04%.

https://rennlist.com/forums/997-foru...lure-mode.html

of course, this poll/site is not an official "random" sampling of all porsche owners and engine failures so it's most likely skewed...however...while the actual failure rate is most probably below 6%, i'd also venture to guess it's far enough above "zero" where it stands out as an inherent weakness.

Willie P

Pls redirect me if I am posting in the wrong place, but the subject matter seems appropriate enough. I am currently in negotiations to purchase a '07 C2S with VIN of WP0AB29967S730456

I think that is a '06 build date - would this be within the window to where IMS should be a significant concern for me? It is being sold by a non Porsche dealer, but I am close with the (Porsche) maintenance department at where it was in-serviced originally and further serviced throughout its life.

thank you so much. -wp

pewter82

Well , I'm not considering my next 997 without a CPO or excellent aftermarket warranty.

Don't care if its 1% or 6% , I'm not digging 20 grand out of savings..

Spiffyjiff

i'm sure some others will chime in but...the car you mention will have the revised bearing which is beefier, more robust etc. it it still prone to failure a la the "catastrophic IMS issue" BUT it seems to be much less common than it's apparently weaker predecessors.

utkinpol

i got PM from a rennlist member last week about his '07 car getting U crack on 6th cylinder. so it looks like it still happens to m97 motors. IMS seems to be a bit more reliable on them but i would agree, more I know more I get under strict opinion that any recent watercooled porsches are money bombs if you have no warranty to cover possible issues.

Neotorque

Respectfully, there is a lot of undue fear being spread on these boards. I personally have an extended warranty for peace of mind, not because it is a clever investment. The people who sell these things have a much better idea than any of us what the average cost of repairs will be, and they sell powertrain warranties on M96 engines at a pretty low rate. In fact, the Platinum all-inclusive warranty I bought was more than twice as much as the comparable powertrain warranty, and the difference between a $100 and $250 deductible would almost double the price of the warranty. What does that say? It says the people who actually have reliable data, whose job it is to make money estimating the cost of repairs to our cars, forecast that most repairs will be small, under $250 items, and that (given the relative costs of such things) are far more likely to occur outside the powertrain.

Let's not forget that the Porsche Boxster with the M96 engine perennially topped reliability lists. Porsche was just named the second most reliable brand besides Lexus this morning (http://bottomline.msnbc.msn.com/_new...-finishes-last).

We're talking about extraordinarily rare problems. That doesn't make them better for the people who have them - thank goodness most of the cases I've seen involve cars still under warranty - but it does mean most of us are losing sleep and fear-mongering over something that is far less likely to kill our car than, say, being hit by a bus. All cars have failures. Lots of cars we compete with - Ferrari, Lamborghini - have scheduled service costs that compete with the price of a (very unlikely) IMS failure. Let's all take a deep breath, get a good warranty if it helps you sleep at night, and enjoy your incredible automobile.

utkinpol

>We're talking about extraordinarily rare problems

well, it is an official factory position. reality seems to differ from that.

Neotorque

In what sense?

utkinpol

in a sense of 'extraordinarily rare' to be 'highly probable'. there are engines that are designed in such way so they cannot produce a catastrophic failure just because of regular wear and tear.
whole family of water-cooled non-GT1 block engines porsche used is designed in the way to blow up if any of major components goes bad - and they do go bad. AOS goes bad - you get hydraulic shock that kills engine when it sucks in oil. pistons and valves are designed in a way that a slightest error in timing results with contact between them - failure. IMS design is done in the way that with time it is destined to fail if bearing is not replaced, and as more cars go into high mileage zone - more cases of this we will see, it happens solely by design.
cooling passages are not done properly and it causes 6th cylinder overheat and subsequent cracks. rod bolts are made from cast steel and stretched when torqued that causes them to tear apart prematurely under load. chain tensioner is designed in such way that it may stop working with time plus timing chain itself gets stretched and starts to rattle - i heard it on almost every 996 and 997 car i saw.
i am too bored to continue this list. deal is - any of those reasons will result with a catastrophic engine failure, purely by design.

all i say here - enjoy this car while it lasts, just be realistic what is it internally.

Neotorque

That's all quite horrific. Do you have any objective facts to back it up? I've cited things like the price of warranties that cover these parts and leading industry surveys which seem to argue differently.

All cars will fail eventually. Everything reliable I've ever seen says that Porsches are among the least likely to do so prematurely.

sullivas

My sympathies, the CPO or equivalent is essential, thank God you had one. I'm keeping a very close eye on my 05, but so far so good at 12000 miles. And I do wind it out to 5-6k rpm occasionally. It sounds great. Nothng in the oil yet.

utkinpol

what facts? pictures of blown motors on a track? I saw 3 last season - 2 boxsters and one 996. try to speak to good mechanics, none of that is such a big secret.

while new those motors run nicely enough. any of high performance motors have their weak spots, it is just M96/M97 got a bit too many at once and their failures are quite difficult to predict so that all in combination makes life a bitch.
plus all repair costs are set so high that in practical reality it is financially pointless to repair this motor, it is usually cheaper just to buy a new one.

again, new motor is $20K. to drop off gearbox and repalce IMS shaft with bearing is a $1500 job or so, so those with old IMS design on 996 and '05 997 cars can simply do it every 10K-15K miles and it will keep major bomb away. at same time they can replace AOS - that does not cost much, may be $300 more.

on my car it is 'new' design that is supposed to be 'better'. there were reports of IMS to blow on '06, '07 and '08 cars too. and it was discussed a lot - when bearing gets old and engine gets old this ims bearing is no longer pre-loaded properly, so istead of rolling its ***** start to slide, so ***** wear off and you get vibrations, then sealant around bearing deteriorates, internal lubricant gets washed away and then it falls apart. like all bearings do.
so what is a total BS in this picture - if it was such a part designed in such a way to last some xxK miles - it has to be replaced as a wear and tear item on a scheduled interval. but on all '06+ motors it cannot be done unless you open up motor, again, big $.

same with with chain - you need to drop motor and crack case open to fix that - it costs astronomical amount of $, so nothing there.

all those issues do happen more often to those who races those cars as they stress them more, but it really just works 'as designed'.

again, i am saying all that for single reason - anybody who runs a piece of very sophisticated machinery should not expect it to be a black box. you need to be realistic of what happens inside. and make your comparisons and your fair assessment. prior to 2009 Z06 cars used to have engines issues too. It is all a matter of choice. it is just anybody who wants to buy an older off warranty porsche with a lot of miles on it got to know what is it inside of that car.

Neotorque

I don't disagree with any of what you've said, but seeing a few blown motors on a track does not mean that all M96/M97 engines are timebombs. Were that the case, there wouldn't be a line of extended warranty places eager to sell you a 4-year powertrain warranty for $2,000, which there is. Every mechanic I've spoken to (and I admit that I am not a mechanic and I have not spoken to a statistically signficant sample) says that these cars are extraordinarily reliable.

None of this means it can't happen. It obviously can, and it is terrible news for those it happens to, especially if they don't have a warranty. But to suggest it is common seems to ignore a lot of objective facts. There are hundreds of thousands, maybe millions, of M96/M97 engines on the road. You've seen 3 fail. There are 40 or 50 reports of failures online, including the OP's. I'm sure there have been hundreds of others, maybe thousands. But that's still less than 1% of what it's out there. Maybe way less.

It's sort of like if you just saw what made the news, you'd think surfers were at a really high risk of getting attacked by a shark. But that's obviously not true. It's just the bad news that makes the news. No one does news stories about the millions of surfers every day who aren't attacked.