You'all scare me...................

[Jake Raby]

Anything mechanical will wear out if the service life is long enough and any machine will break. No engine is completely bullet proof when making a decent amount of power. All this is easy for me to state and understand as I've been breaking stuff my entire life.

The M96 does have it's share of problems and the majority of these could have been avoided if the MFR had stated a more definitive set of service directives that require scheduled replacements of some high risk components.

A good example is the water pump, if the directives would have stated to change the water pump after 3 years, no matter the mileage I would have 4 cars on our property right now with failed engines. If the IMS bearing retrofit was required at 40K miles most of the cars we see with IMS failures also would avoid the issues as well.

With other cars its totally normal to change a timing belt at 60K miles and doing so is required, if not the engine will implode just like an M96 does with an IMS bearing failure. changing these timing belts can easily cost as much as an IMSR procedure. The difference is the directives tell technicians and owners that this needs to be done.

The M96 was hyped up to be much more reliable than it's aircooled predecessors which made the cars more appealing to a different group of driver. Unfortunately that group of driver's bought the car for the wrong reason in lots of instances and have treated it like a Toyota or Honda and thats what has made a big impact on the failures we see.

Drive the car like a Porsche, maintain the car like a Porsche and use your common sense to replace components before they fail and you'll have a much better experience with the M96 powered Porsche.

That said, I had a car come in on Friday for an IMSR (04 Boxster) that was to be done as a preventive measure. In our pre- IMSR evaluation we found that the engine had compression numbers 50-60 PSI low on all cylinders. We talked to the owner and he said that 10 days before the car was shipped to us that it had an episode where it smoked briefly and then started to run poorly.

With 34K on the clock and having been insanely maintained, this one is unexplained as to why it lost compression on all 6 cylinders evenly. What was going to be a quick IMSR/ Water pump/ AOS upgrade turned into another 18K expenditure. This one surprised all of us involved and it'll be interesting to see what truly took the engine out.

Its a good thing this car came to us for the IMSR as we do an extensive pre-eval that showed this issue before we spent 3,500.00 of the owner's money to upgrade an engine that was already failed, but still ran.

[mikefocke]

And I'd surmise no one knows for sure exactly what it is, not even Porsche (as many of the cars Jake sees wouldn't be in their statistics).

My impression is you have a 1-3% chance of failure per year driven. Maybe more if poorly maintained or seldom driven. On the lower side is you do things right.

IIRC: The highest mileage Porsche Boxster I know of (Marc) is over 238k miles on the original engine. Pedro's engine blew at 207k on the track (after lots of track/AX time) but not from an IMS failure. Both are older cars with lots of miles. Both have original IMSs. Both were maintained much better than the book by Porsche knowledgeable folk. One was generally dealer maintained, one was owner maintained.

[JFP in PA]

Correction Mike, Pedro's engine had the LN retrofit in it when it blew, I believe from a rod failure not related to the IMS...................

[SeaNile31]

All this IMS talk has be once again debating an 05 S and doing the IMS upgrade or spending more for an 09 S.

[mikefocke]

You may be right on Pedro's engine...and the LN bearing was put in at what mileage? Probably 160k+ as it hasn't been out that long and my last said the longest mileage on the LN part was at about 30k.

I was responding to multiple points from prior posters..that there was a 50% failure rate and that there were few cars with many many miles on an IMS. Neither of which assertions my readings cause me to agree with. And trying to use Pedro's car as an example because it had so many miles on the original engine and failed not from an IMS problem and not on normal roads in normal driving style..though perhaps it was for him.

And if someone is worried about that risk, what about the other 4-6 potential causes of failure that we hear of? I figure I've over- improved too many of my cars.

What are the odds of 3 tail lights burning out on the wife's Acura at the same time? I replaced all 4 but then the cost was $2.50 for the extra bulb and my labor is cheap.

[JFP in PA]

I have to agree with some of your points Mike; I don't think the IMS failure rate is anywhere near 50%; or even 25% for that matter. Problem is that we are never going to know the real failure rate; that said, I know for a fact it does happen, and at some rate that is high enough to be discomforting to anyone with an M96/7, including the post 2006 units with the "last attempt" large diameter IMS bearing. The biggest issues are that it often gives little, if any warning; and the results are catastrophic, both mechanically and financially. And, yes, there are sevaral examples of very high mile cars with the OEM IMS in them.

Fortunately, there are ways to deal with it. So rather than sit around and endlessly debate it, perhaps it is time for those concerned to become pro-active.

[coreseller]

Originally Posted by JFP in PA

I have to agree with some of your points Mike; I don't think the IMS failure rate is anywhere near 50%; or even 25% for that matter. Problem is that we are never going to know the real failure rate; that said, I know for a fact it does happen, and at some rate that is high enough to be discomforting to anyone with an M96/7, including the post 2006 units with the "last attempt" large diameter IMS bearing. The biggest issues are that it often gives little, if any warning; and the results are catastrophic, both mechanically and financially. And, yes, there are sevaral examples of very high mile cars with the OEM IMS in them.

Fortunately, there are ways to deal with it. So rather than sit around and endlessly debate it, perhaps it is time for those concerned to become pro-active.

Game, Set, Match.

[JTP]

Originally Posted by mikefocke

my last said the longest mileage on the LN part was at about 30k.

Only 30k on the longest run IMSR? That's it? I wish I could be a test bed for it, I drove my Box 18,000 miles in the last 7 months and by 12 months I'd be close to 30k. I'm paranoid about the IMS, water pump, AOS, etc but I'm trying to keep on the maintenence and drive it alot.

[JFP in PA]

I don't think people realize how low the mileage is on a lot of these cars are due to limited or seasonal use; we had an 01S up on the lift today getting it ready to go into hibernation for the winter, original owner, 9,734 miles.................

When it comes to the LN retrofit, look at the numbers differently: Over 1,000 units on the road, zero failures...................