Conan Dombroski

I've done the research and decided to have my IMS replaced just as a form of insurance. I figure $2000 (quoted from the dealer) is pretty cheap for 65K miles. So I contacted my dealership's Porsche service rep. This is his response:

I'm not sure what to do at this point. Even if I want to proceed, what parts do I get? The rep told me customers normally buy the parts and bring them in. Any advice?

hollywood1053

My engine number is 68513751 and was a late May '05 build date.
This engine number is almost 1000 after the 'cut-over' number Porsche references in the class action suit where the newer, larger bearing was implemented.
Yours looks to be well after mine. Too much actually being stated that it's an M96 engine. Are you sure that number is accurate?

Conan Dombroski

I need to get under there myself and double check. They may have made a mistake, but that's the number they told me (copy-pasted right from the email.)

captainbaker

Looks like you have the larger non serviceable IMS, which has not gained notoriety for failure.

If you want to proceed, the below link is one place to get your parts. But notice in the description, they dont recommend changing out the IMS because it entails disassembling the engine.
http://imsretrofit.com/my06-08/

ronvanr

Where do you find your engine number? I too have a car built in May of 2005.

hollywood1053

The number I referenced came directly from the COA on my car.
The number is also stamped somewhere on the engine block.

wjk_glynn

My 997.2 owners manual shows you where to find your engine number (under "Vehicle Identification, Technical Data").

Does the .1 owners manual have the same info?

jhbrennan

Yes - page 285.

ronvanr

Do you know what the engine "cut-over" number was, that was listed in the class action suet. Based on the above info, circa 68512751??

johnireland

If you have a 997.1 with the non-serviceable IMSB you should still have the rear seal removed so that the bearing gets lubrication from the engine oil. The Porsche Class Action settlement states that these versions of the bearing have the same failure rate as the original dual row bearings in the early 3.4 engines....1% or a little less. Not as good as the Mezger and 997.2 engines...and they are not recommended by Porsche Motor Sports as track or performance rated engines...but certainly good road engines.

Petza914

It's not 100% guaranteed that after X engine # only large bearings were used. If you have a late '05 car, the only way to know for sure is to inspect the nut that's used on the IMS bearing flange.

Nut that corresponds to later larger row single bearing is on the left - smaller bearings on the right


My engine #s are M97_0168512123 & M97_01685121680. Both are large bearing cars personally verified by me after dropping the trans during PPIs.

ronvanr

My engine number (C2) is M96/05 69509429, fairy close to what Conan's engine number is (69504482), but nearly a million off from Hollywood's (68513751) engine number is. Sounds like engine number isn't a sure things for determining the type of IMS bearing you have, But I wonder why the big difference in engine numbers for M96 engines made in May 2005?

I'm guessing the digit after the 6 might represent something other then in which order an engine was made??

semicycler

Some confusion here. Technically there are three different serial number types for the three engine variants in our cars - base model M96.05 3.6L engines, S-model M97.01 3.8L engines, and the X51 power kit M97.01S 3.8L engines. All three have slightly different engine serial number formats.

For S-model non-X51 M97.01 engines the serial number is of the format M97/0168YXXXXX. The last 8 digits matter and are the following format:
685XXXXX = M97 for MY05
686XXXXX = M97 for MY06
687XXXXX = M97 for MY07

So the first two digits are 68, followed by the year digit, followed by a five digit serial number. But the full serial is M97/0168YXXXXX.

For X51 engines I believe the format is M97/01S68YXXXXX (added 'S' between 01 and 68).

3.6L base engines have a similar format M96/0569YXXXXX (not positive on the 05, can someone check?).

With replacement engines there is an 'AT' in front of the final eight digits. So a S-model 3.8L factory replacement engine the format would look like M97/01AT68YXXXXX.

Conan - Your service tech did not give you the complete code stamped on the engine. Crawl under the car with a cell phone and snap a picture. You might need to clean the area first.

hollywood1053 - by your serial number you have a 3.8L engine, not a base model 2005 3.6L engine like Conan. Post your full number stamped on the block and confirm what engine you have.

ronvar - your number looks valid for a 2005 M96.05 3.6L engine (695XXXXX)

BigJule

Hello, I just acquired a 2006 997 Base and my engine # is M96/0569605498, very confusing as far as IMS is concerned. Cheers, J.

semicycler

Yours is a 2006. No worries about the IMS bearing as it has the larger, more reliable bearing. Only early 2005 cars potentially have the smaller bearing that was part of the class action lawsuit. For those cars fortunately the bearing is replaceable, but does require dropping the transmission.