Buying used Boxster S - IMS flange replaced but not IMS bearing?
 

Hello all!

I'm new to the forum but have been lurking for quite a while. Been seriously considering purchasing a 986. I found a 2000 Boxster S at a dealer and it seems like a great opportunity (68k miles, service records dating back to 16k miles in '07, new tires, new clutch, new spark plugs, recent convertible top maint.).

Here is my concern. While reviewing the service records, Porsche replaced the clutch at 55k (along with new RMS) and also upgraded the intermediate shaft flange to the newer design, however, the paperwork says nothing about replacing the IMS bearing! The paperwork below states "Replaced rear main seal and intermediate flange and hardware due to oil leakage." Should I be concerned that the bearing will still grenade at any time? What are the chances they inspected it and found it was OK? I don't mind calling the Porsche shop tomorrow to see if I can get more details, but I'm not sure if they will have any more than what shows up below. Thanks for the help!

http://986forum.com/forums/uploads01...1406768508.jpg

The design of the IMS flange was changed due to oil leakage problems. The old design used a rubber O-ring. The replacement new design used a rectangular 3-rib rubber gasket that doesn't leak. It is not unexpected that it would get changed.

BUT you are lucky. You have the paperwork....check the flange number. You should be able to determine whether you have the dual-row IMSB (likely) or the single-row IMSB (random in 2000) by the part number. Download the free PET from the Porsche site (parts breakdown).

I've downloaded the PET and searched for the part number and it shows up on page 22 (of 472). Trouble is, the PET lists "2004" in the header of all the pages. I can't seem to find any part variations (seems like the catalog is for a single model year) How would I be able to determine whether I have a single or double row bearing from the illustration? The flange is p/n: 996-105-017-02. Thanks.

In 2000 there are no accurate directives that will clearly identify which bearing is fitted. 2000 and 2001 both require a visual inspection to quantify which bearing is fitted.. Porsche kept the records and did a poor job of it based on our direct experience.

The IMS flange was changed from a single O ring style to a triple lipped style seal due to leakage issues. That said, the fact that it was changed tells me that you have an early 2000 MY and that would indicate a dual row IMSB is fitted.

I have never seen a single row bearing fitted with the early O ring style flange. After 399 retrofit procedures, including the very first one, well, we still continue to break new ground.

Look on page 469 of the PET for an explanation of year vs. S vs. non-S etc etc

You have a M96.21 engine. The "M >>" means engine serial number UP TO the #. So you had the early dual-row IMSB flange installed. You only know this because the dealer installed the flange and wrote the part number down.

Thanks for the help guys. Sounds like I can rest a bit easier knowing it has the dual row IMSB! (Please, correct me if I'm wrong here) I will still plan to install an upgrade kit once it is time for a new clutch, but that won't be for a while since it was done recently.

And thanks Dennis for the clarification on interpreting the PET. Much clearer now!

The problem with the dual row bearing is it takes too long to fail... The bearing has twice as many components to share radial and longitudinal loads, so symptoms of failure are non- existent for a long period of time. That means that the dual row bearing can be filling the oil system with ferro- magnetic debris that the oil filter will byass into the primary oil system and feed to the main and rod bearings, along with every other internally lubricated component within the engine.

We see more widespread collateral damage from dual row bearing engines than all others combined due to this characteristic. The longer an engine runs with contaminated oil, the lesser the chances are of ever resurrecting the engine once IMSB failure symptoms do present themselves.

Single row engines skip stage 3 bearing failure altogether and just break, which can be a good thing for the rest of the engine.

What about an oil filter adapter that allows a spin-on filter with no bypass?

Takes too long to fail
 

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Am I reading this correctly: this car went in for a new clutch early in 2012, when the LNE dual row bearing was already available for some time (or at least a less expensive non-LNE replacement) and this shop Jim Ellis had everything apart and kept the original IMSB in? If so, I don't get that. What serviceable bearing, tied to a make or break event, lasts forever?

They even had to lock the cams down and pull the tensioners so they could remove the IMS flange. It's only another half hour to remove and install the IMS bearing. In my case, once I got the flange off the IMS bearing swap was real easy other than having to puzzle out how to get that spriro-loc ring thing in place. A professional mechanic should already know how to do that.

You can tell they pulled one tensioner because they billed for part 900 123 147 30, which is the sealing ring for a chain tensioner.

I wonder whether they pulled the rear rubber seal on the IMS bearing, which is the hillbilly fix for an OEM dual-row IMS bearing.

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That's because Porsche dealers on are strict orders NOT to retrofit LN or any other non-OEM IMS bearings. Pioneer of San Diego (now SD Porsche ) did a few years ago, than had to stop.
BTW I had sranton's warranty work done to my CPO '02 in '04: later RMS and IMS flange, but no IMS bearing activity.

74K and goes like a scalded cat, with dozens of autocrosses.

[QUOTE=Jake Raby;412459]The problem with the dual row bearing is it takes too long to fail...
LMFAO
Freudian slip coming from the Jake??
In all seriousness, Jake's bearing is an honest product and a great solution to a disastrous manufacturer defect. I'm running one in my 996. Sranton, I think you're on the right track.

Must have been a battin down the hatches thing for the class action litigation.

So I'm not sure what would be the point in continuing now that the case has been settled.

[QUOTE=j.fro;412482] No, The dual row bearing remains at stage 3 failure far too long.. Trust that doesn't mean that I am saying that it takes too long to begin failing, because I am not saying that.

Once the bearing starts to fail it emits debris for way too long.. The bearing has already failed, it just allows the engine to run too long as all the processes take longer to progress into complete engine failure.

Last week we pulled apart a core that had a failing dual row IMSB. The bearing was still together and had not reached stage 4 failure yet. The crankshaft, every cam journal, and all the cylinders, the main oil pump and scavenge oil pumps were all wasted.

It was a classic example of a dual row bearing dying a slow, symptomless death and creating engine wide collateral damage of disastrous proportions.

While the dealers had a "campaign" going to replace the early design flange covers which were leaking, for the most part (unless they were one of the more renegade dealers), they did not touch the bearing itself.

Boy would I love to see how many of these ended up going down anyway.
Talk about snatching defeat from the jaws of victory.

I wouldn't say completely symptomless. Thats where blackstone comes in.

Because at that time we had yet to release the IMSR procedure. Dealers and everyone else said that what we do routinely today in regard to IMSR procedures were impossible;e to do. The dual row bearing was believed to be impossible to remove, and dealerships were among the last to finally "cave" and admit that the bearing was serviceable with our procedure and tooling.

We were performing the "impossible" 3 years before it was ever released. As we say "The difficult we do right away, the impossible takes a little longer".

Not entirely correct. Symptoms are generally defined as things that present themselves without being sought out. A UOA is an a

If particles are greater than 30 micron, a particulate test is required to find them and thats only offered by Caterpillar (hardly anyone knows the difference and UOA companies won't ever mention a particulate tests). I have seen engines with failing IMSB pass a UOA less than 800 miles before they completely failed. UOA is a very poor method of identifying IMSB issues, and always has been. A visual inspection of oil sumps and filter housings is more effective than UOA in my direct experience. That said, I have a ledger with over 600 UOA inside it on my desk and we carry out 12-15 samples per week developing lubricants and evaluating our engines.

Too many Oil Analysts believe in Unicorns and Rainbows, they positively reassure everyone and just say "lets watch this closer and maybe shorten the service interval"… In other words they are saying "we really don't know a damn thing about the materials that comprise your engine, but if it doesn't blow up before the next oil service you should send us another sample".