PCA IMS video left me more confused...

I have an 03 C4S that received a crate engine under warranty at 36k miles due to IMS failure. The crate engine was installed in November 2009 with a new clutch.I now have 56k on the vehicle so right at 20k on new engine. In one respect, this is a prime candidate for failure as even on the new engine, low mileage per year. However, I am not a statistician but I believe my chances of failure dropped due to the fact I am on a second motor... or you could argue its the same. I am not sure. Anyway, for complete piece of mind I should replace the IMS bearing but PCA video implies I should have latest larger diameter single row with lowest incidence of failure. Best part is the only way to find out is to remove the transmission and once I am in there, and have spent money to R&R transmission, I should probably replace bearing and clutch. Hence my dilemma... any input for me to consider to help me make my decision would be greatly appreciated, Thanks.

As I understand it...odds are you have the larger "non-serviceable"(without splitting the engine cases) bearing depending on engine factory build date. Yes only way to know is drop transmission and visually check. Sorry...

The failure rate on the large bearing (**almost definitely in a motor replaced in '09 - unless it was kicking around a warehouse since '05...if you can determine the manufacture date of the engine you should be able to figure it out) is extremely low. What sort of oil change intervals have you been doing over the last 20k miles? If you've been doing 6 months or 5k miles your chances of failure are even lower. If you get in there and remove the outer seal they get lower still... Good luck

Yup, that's about it. I will pull engine number later and see what I can learn but it is obviously an M96 engine so not sure how I could have the later non serviceable variant. I am in Philly area and have found a local Indy that has good experience and gave me confidence when we spoke. I may just have him drop the transmission and have a look. I mean, I could drop it myself in the garage but that's pointless as if its replaceable, I would like the trace ability from a certified LN installer.

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My Indy suggested this. I will get oil current sample back shortly and seen no increase in wear metals to date

That's a good sign. There were at least 5 revisions of the M96 engine. The large bearing was used in the last revision...(I think post '05/'06???). If you remove the grease seal and it looks like there's no bearing damage (still grease in there, no metal) you'll probably be fine. If you decide to replace the bearing, you'll be looking at BIG MONEY (drop motor, remove and ancillary equipment, split case halves, find other things that "might as well replace while we're in there"...etc...) - make sure they give you a comprehensive "worst case scenario" of what may be needed... Good luck

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Great info. If its latest bearing AND looks healthy, I will pull seal and take no further action other than driving it hard and smiling.

Don’t mess with it. You are more than fine. As stated, they started using the larger bearing in ‘05. I had a car with an ‘06 crate engine replacement and it was the larger bearing. It was flogged mercilessly as a race car and never showed a bit of wear in the oil samples.

I thought I made the point clear enough that once a bearing was superseded, no more engines were produced with that bearing style. In these cases the bearing that was used would be the same as what was being built at that time, and supplied in new cars. In this scenario you DO have the M97 diameter IMSB, as by 2009 M97 based engines were already well away from the factory, and had been fitted with the later style, large diameter bearing since mid 2005. The ONLY way that you'd have any other previous IMSB is IF your engine had sat on the shelf somewhere since prior to mid 2005. One way to tell this is by the style of fasteners used to attach the case halves, and etc. If they are E10 fasteners, then its likely not the case. If they are 10mm hex, then it could have sat around for years. The fasteners changed alongside the IMSB, but like everything else, a few months one way or the other can break the rules. You have a 95% chance that the engine has the M97 bearing. In that case, just drive the damn thing, and keep the oil serviced 5K miles/ 6 months. If you really want to know, slide the tranny back 1" and look at the flange, like I say over and over, and over again, THIS is the THE only way to conclusively know what bearing an engine has.

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More great info. I could do transmission slide in garage. I have bore scope. Perhaps I will just drill tranny case for bore scope near bell housing and be done ;-) I am very new to ownership and getting up to speed on all issues. While aware of IMS prior to purchase I still have a lot to learn.

Ok, Just for giggles I pulled the engine number M96/03AT66568487 That gives me a an M96, 6 cyclinder (duh), 6th version of engine manufactured in 05 with serial number 68487 AT tells me reman ...so are we thinking it was re-manufactured in 05 ? As earlier poster said, absolutely no way to tell which bearing it has unless 6th version tells us something. Did seem to be only 6 star fastners and no 10mm hex.

So manufactured in ‘05 and has E10 bolts. Still planning on drilling a hole in the tranny or are you comfortable now?

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That number doesn't mean a damn thing in regard to the IMSB that's fitted. No use in even looking at it.

I thought the PCA IMS video was pretty clear. The replacement engine may or may not be a third generation M96/97 engine with the "larger single row IMSB"...depends on engine manufacture date; and only an actual visual inspection (tranny out) can make the determination. relinuca

Thanks all for the informative feedback. To be clear, the message was received loud and clear that visual inspection is ONLY way to be clear which bearing fitted. If you read my posts I say as much and discuss one not serous and one serous way I may do just that. I shared the engine number as I thought it interesting that a reman engine fitted November 2009 was in theory a 2005 engine. I was hoping someone may share info that all reman engines keep core engine number from 'donor' or some other explanation other than it sat on a shelf for 4 years plus. Surely any owner with a replacement engine would be just as curious as to its history, build spec etc. I did learn its version 6 whatever that may be and was hoping to learn something about what version 6 is/was as opposed to just the one after version 5. Perhaps my writing style confused some. I also wanted to confirm that after I learned later engines may have different fasteners, mine did in fact have those fasteners. But you can all step back off the ledge, I am under no illusion that the ONLY way to know which bearing is fitted is to phsyically see the bearing itself. Thanks again.