IMS job half-done - My IMS was perfect when removed.

[mountainman]

My 2002 carrerra 4 IMS failed at 46K which I find absolutely reprehensible for a a high priced performance car. Never tracked and always carefully serviced. The last service was less than 2K miles before it self destructed with no debris having ever shown up in the filter and no other symptoms. Happened at 60 mph on a PCA outing. From the porsche dealer all the way to porsche customer service rep, everyone was very sympathetic but said that because it was out of warranty that was just tough. $20,000 later I was back on the road. Due to the number of failures of this part, I see this as a design flaw and a failure of porsche engineering to address it. It would appear that the only safe way to protect yourself is to spend $2K every 25K miles to put in a new bearing just in case. After venting a bit, let me say that I bought my first porsche in 1964 and I currently have three of them, so I have plenty of brand loyalty. I just feel that porsche has let us down in this situation. I now have 25K miles on the new engine and I really don't feel secure that I won't have an impending failure with it soon.
From my reading about the guardian a significant number of opinions are that when you get the warning it is probably too late to save the engine and you are still looking at a rebuild, but you have maybe saved the core. Are we better off just to have a milage schedule to spend 2 grand to put in a new bearing. If so, what milage would be safe?

[mikefocke]

There is no such thing as absolute safety. In any engine or transmission or any other part. They all fail sometime..its just luck when. As to when they fail...anywhere from 6k to 250k in postings I've seen.

I don't know where you got the impression that the Guardian would only warn when the engine was toast. I know the testing of the Guardian included the insertion of a IMS bearing known to be going bad in a perfectly good engine, the installation of the Guardian, the driving of the car until the Guardian signaled a problem and then the examination of the bearing condition. The engine was saved. You have to stop when the buzzer goes off, yes. But the intent of the Guardian is to catch the problem early enough that you can save the engine.

Your replacement engine (if from Porsche) certainly also has a design/materials-flawed bearing. Which one you wouldn't know until you had pulled the transmission off and inspected the IMS area. So if you are feeling insecure, you could go get one of the LN bearing kits installed and have greater assurance. You could do it either as a preventative measure or when the Guardian told you you needed to inspect the bearing condition.

[shadrach74]

Originally Posted by mikefocke

There is no such thing as absolute safety. In any engine or transmission or any other part. They all fail sometime..its just luck when. As to when they fail...anywhere from 6k to 250k in postings I've seen.

This is completely untrue of any design...it may be true with 986/987/996 models. But there are plenty of machines out there that if properly assembled with non defective parts have incredible reliability rates. Boxsters are an absolute ball to drive, but far from a design tour de force in terms of reliability...in fact they're pretty piss poor IMHO...

[mikefocke]

Well Shad, my experience differs. I've owned/controlled-the maintenance-for an average of 3 cars for the last 53 years and had everything from a Plymouth, Dodge (4), Pontiac, Alfa, Acura have a major internal mechanical failure resulting in the need to rebuild or replace the engine or transmission. That doesn't count probably 30 cars replaced for premature rust reasons. Or others which were just generally so unreliable and unfixable (914) I gave up on them. I maintain the cars better than the manufacturers ask and still there are random failures.

Yes, I had a secretary who had about 400k on her 4-cyl Pontiac with the original clutch and never any internal engine work. Her driving style and the luck of assembly just happened to coincide. But for every one of those, there is someone early on that bell curve of reliability.

They all fail sometime. And not just M96s.

[shadrach74]

Mike, my experience differs from yours. I've only been driving for about 20 years, but have taken 3 vehicles to well past 200k miles on original engines. When I sold my 1985 merc 190E it had 265k, the 1987 BMW 325is had 215k. 1992 Audi 200 turbo had 245k. My current DD is a Lexus GS 400 with 210k on engine and trans.

[mikefocke]

And there are Boxsters which go 200-250k. Don't judge by a limited sample. Parts that rub against something wear, simple fact of life. And they fail on a bell curve with some going for a long time and some failing on the left hand side of the curve.

I'm glad you had great luck, I haven't. My max on a motor was 105k and its replacement lasted 2k. Next motor was 15k when I junked the car (Japanese motor) because of body rust. My environment was DC 4-season urban commuting 10 miles to work, 2 to the store and 250 to grandpas. Oil every 3k no matter what the dealer/maker said. 2 Boxsters, no failures over 5+ years. Not that they couldn't have and not that others haven't failed them and not that I make too much of the statistics of a sample that size.

[feelyx]

Originally Posted by mountainman

My 2002 carrerra 4 IMS failed at 46K which I find absolutely reprehensible for a a high priced performance car. Never tracked and always carefully serviced. The last service was less than 2K miles before it self destructed with no debris having ever shown up in the filter and no other symptoms. Happened at 60 mph on a PCA outing. From the porsche dealer all the way to porsche customer service rep, everyone was very sympathetic but said that because it was out of warranty that was just tough. $20,000 later I was back on the road. Due to the number of failures of this part, I see this as a design flaw and a failure of porsche engineering to address it. It would appear that the only safe way to protect yourself is to spend $2K every 25K miles to put in a new bearing just in case. After venting a bit, let me say that I bought my first porsche in 1964 and I currently have three of them, so I have plenty of brand loyalty. I just feel that porsche has let us down in this situation. I now have 25K miles on the new engine and I really don't feel secure that I won't have an impending failure with it soon.
From my reading about the guardian a significant number of opinions are that when you get the warning it is probably too late to save the engine and you are still looking at a rebuild, but you have maybe saved the core. Are we better off just to have a milage schedule to spend 2 grand to put in a new bearing. If so, what milage would be safe?

Unfortunately, if Porsche put in a new engine, chances are they put one in that the bearing is not easily replaceable. It will cost alot more than $2k as you would need to split the cases. Yes the guardian in your case would be very useful as the alert would save your engine from failure.