Boxster Engine Failures - Some Clarity Please
 

I know this has been beaten to death a thousand times, and I've done a lot of reading both before and after buying my '98 (which was delivered new in December of '97), but I'm not clear on what modes of failure affect specific year models. Any input on the below would be greatly appreciated:

1. The prior owner had the IMS replaced with an LN Engineering version, and at the same time, the RMS replaced with the updated version, at around 27K miles. The car currently has around 36K, so I'm assuming these two major items won't be an issue near-term.

2. I've read about "D-Chunk," but my reading indicates that it was most prevalent in cars manufactured over a certain period for the '99 model year. Does this mean my '98 is less likely to experience this failure?

I know there are a dozen more, but most don't cause catastrophic failure, with the exception of the rod bolt issue and chain tensioner issue.

Is my understanding of the above correct?

Oh, and one other question...Does it make sense to upgrade the tensioners to the updated version as a preemptive measure?

Thanks!

I think the current count of failures is up to 40 or so. Someone can correct me if I am low or high. As long as you have the IMS replaced and the RMS, you routinely replace the oil and miscellaneous other fluids, and keep up on components that suggest they may be failing (water pump), drive it like you stole it and don't look back. Not that I am condoning or suggesting reckless driving. Some components are suggested that you replace them in specified intervals, but you can research those and determine your course of action (water pump, thermostat, ect..).

Otherwise, if these fears of catastrophic events are going to be something that keeps you up at night ....sell it. I don't mean to be harsh, but that is the realization I had to go through with my 2004 Boxster S, and I sleep just fine now. Most German vehicles have some sort of issue that will cause a catastrophic failure to the vehicle, the boxster is no different.

Someone smarter than me will need to answer the tensioner question. I have yet to replace mine, but that does not mean anything.

all mechanical things will eventually fail

I do believe all living things eventually fail also.

Any car can experience any kind of failure, but the 986 specific ones are IMS, RMS, D-chunk, and slipped sleeve. You can catch RMS by an oil drip that often occurs before the failure, and D-Chunk and slipped sleeve are now exceedingly rare on 15+ year old cars, as most occurred early on and where replaced under warranty.

The 986 was prone to D-chunk failure, where a part of the cylinder would fail (a D shaped chunk would break off), this most commonly occurred before/around 30k miles, and almost all of these failures where replaced under warranty. It would be rare, for a 986 to experience that failure now, considering the age/milage of most 986's. The best defense against this failure is to let the car properly heat up before revving the engine over 3000rpm.

Slipped sleeve failure is not the same as d-chunk, and affected only a few months of '99 production. Due to the unexpected popularity of the 986, Porsche could not keep up with demand and ended up using cylinder sleeves on some 1999 986's. Due to a defect some of the sleeves failed, resulting in engine failure. The months affected are though to be: 10/1/1998 to 3/31/1999, you can check your manufacture date on the driver's door sticker. However, most of the 986's affected by slipped sleeve would have failed by now (again though to happen by or around 30k miles), and it would be rare to have a slipped sleeve failure these days.

My 1999 986 with 95k miles is in the date range affected, and no issues so far. :cheers:

I read somewhere that some 99's were less prone to an IMS failure for some reason, is that true or some 99 owner wishfull thinking BS?

Seadweller...
Have a read of Barry Hart's Hartech UK take on the M96 engines - both the good parts and the warts. He is the Jake Raby of England, and has come up with very similar conclusions to Raby, though he goes about the repairs a little differently.
He gives a very good (though long) description below.
Porsche servicing, repairs, engine rebuilds, reconditioned wishbones and cars for sale - near Bolton, North West England. See Buyers Guide (part 4 is the most appropriate).

Porsche 'redesigned' the IMS in 2001. The post-01 986's with the redesigned IMS are the ones that the IMS issue is primarily concerned with, and tend to have a higher failure rate than what would be considered normal (lots of debate about the percentages, and lots of threads on this as well). Pre-01 986's can experience IMS failure, but it is about as common as with any other car, so not that common. However, a lot of the companies selling IMS retrofits tend to ignore the pre/post 2001 differences for obvious reasons. :cheers:

Entropy is a b*tch. :eek:

About 8 times less for the '99 if it has the original engine. Figures from about 5 years ago and the higher figure admitted to at the time by Porsche in a lawsuit.

Having said that, the worst case was a 1% per car year figure as age and wear have added to the probability since then.

That explains the longevity of my 99 withoriginal untouched engine at 200k miles and it runs like new

An observer owning a C63 AMG which are prone to broken headbolts. Having read Porsche owners' frustrations at the class action "payouts" the entrophy card is played big time by the defense lawyers for Porsche. "Hey, car parts wear out, what's the beef?" To many the beef is that Porsches should run strong AND last. You know, like in Sebring, LeMans, on and on. Who in this forum believe service only by a dealer avoids the IMS and other problems? But I think I read payout amounts depend somewhat on dealer service.