Having been a long time 996 owner with a dual row IMS bearing, I want to move up to a 996.
How concerned should I be re: IMS bearing failure.
The car I am looking at has 58k mi. if that makes a difference.
TIA

 

Slight mistake, I meant 997.

 

Not much you can do about it other than checking the engine number and seeing if you have the larger or smaller IMS. There are a few sites you can go to to check, just google it. Engine number is on the bottom of the engine, under the car, driver's side behind the rear wheel. Easy to find but might be difficult to read due to the age of the car. Take a pic and then enlarge it. I have 2005 C2S, larger IMS and so far it's fine at 55k miles. But you never know. Replacing the larger IMS is a lot more work.

 

2005 was the crossover year. Early builds had the older single row bearing like the 996 and later 05 builds had the larger improved bearing. Have the car inspected and find out which one it has. If it's the older bearing it can be replaced just like in the 996. If it's the newer improved bearing you can leave it alone because failures are rare and its extremely hard to replace. There are lists of engine numbers and build dates that are reasonably accurate to tell which bearing it has but the only way to know for sure is to look. If the nut on the IMS flange is a 13mm hex then it's the older style bearing. If the nut is 22mm then it's the newer bearing.

 

It’s a gamble since some have no issue and some do.
If it’s a later 2005 build it may have the larger bearing. You can use the engine serial number to verify which one it is. The number is visible from underneath the driver side rear.
If it has the smaller bearing, budget/negotiate $ for the upgrade.

 

Found this:
For 3.8L motors, up to M97/01 68509790 has the smaller IMS bearing and Engine number from M97/01 68509791 has the larger revised IMS.

For 3.6L motors, if the engine s/n is M96/05 69507476 and up it has the larger bearing.

 

Thanks all.
I am also looking at a 2007 S with 53k mi.
As I understand it, the 3.8 is pretty much a good one except for possible bore scoring, correct?

 

Contrary to popular opinion, if you are shopping 997.1 cars, I think it is an advantage to find one with the smaller single-row IMS. It is easy/ier to replace than the larger double-row and you can replace it with the LN solution (https://lnengineering.com/shop-by-mo...s-my00-05.html) and never have to worry about that part again. I think building in the cost of the IMS replacement on the smaller-bearing cars is a no-brainer for more peace of mind. When I bought my first 997.1 Carrera S, I found one with the IMS already replaced with the LN solution. Not many .1s with the larger bearing have been replaced because it is a PITA to do so. Unfortunately, my car suffered bore scoring, which is another matter...

 

3.6 or 3.8 makes no difference when it comes to IMS. If you like that 2007 that will have the larger improved bearing. Just get a thorough PPI with bore scope before buying.

 

I've got a bit of experience - As long as the 2005 has the larger bearing you are ok. IMS issues very tiny% on the larger bearing.
**BUT do not buy any 997 unless you have Bore Scope Inspection - Bore Scoring is found in every model whether non-S, S or C4S
It is a must to get Bore Scope Insp. - I have owned 6 997's in total and would never buy one unless fully inspected.
Yes it costs an extra $350-$400 for the Bore Scope Insp but gotta do it.

I just bought my 6th 2006 997 C4 and looked at and PPI/Bore Scoped 2 prior 997's (06 997S w/80K miles & 07 997S w/90K miles) within the last 2 months and those 2 had significant Bore Scoring and one has a vertical crack in cylinder wall.
The 2006 C4 that I just purchased passed the Bore Scope Inspection with flying colors - It has 106K miles and cylinder walls are excellent condition.
**Make sure your Bore Scope Inspection comes with photos of each cylinder - I have 3 photos of each cylinder wall.

Here are 3 photos from my recent BS insp of 3 of the 6 cylinders as an example of what all 6 cylinders look like:

 

Groove - didn't you last C2 non-S (cabIi believe) have 80K miles and great bores. Maybe something to be said for the 3.6 vs 3.8, or maybe just anecdotal / myth. I know neither are immune to BS, but 3.6 less so maybe?

 

Yes - my C4 Cab 3.6 had excellent Bore Scope Insp.as well and the C4 coupe 3.6 I just bought last week.
I have to tell you when you have the Bore Scope Photos to show to buyer, makes transaction simple and clean. Puts to rest any uncertainty.

4-5 years ago BS Inspection wasn't really a topic and now that the cars are reaching higher miles there are many more crappy stories of high oil consumption, poor running engine/etc due to Bore Scoring related issues.
Like I said above Bore Scope Inspection a must for everyone.

Thanks to fellow member and buddy Kellen, I got the Lobster fork wheels mounted on my car today as well as Bluetooth and new Temp/Fan Switches.
H&R springs getting installed in a couple of weeks. Also having front differential oil changed.

 

Don’t sweat the IMS, just swap it to an LN when you do the clutch if it is the smaller bearing, if it isn’t remove the seal as recommended by FSI.

 

how did you find out if you had bore scoring? Oil consumption? How many miles? Where did you send it for a rebuild?

 

On the contrary, I have to disagree. I would personally stay away from an early 2005 997.1 engine with the smaller IMS Bearing (Unless the IMS Bearing has been changed out already) because the 997.1 earlier engines are more problematic.
The later IMS Bearing is more robust and much less failure rate. And we all have to remember the failure rate is extremely low when you factor in the # of cars produced. I think the bigger issue is Bore Scoring and why I suggest to anyone buying a 997.2 or 997.2 car have Bore Score Inspection.
As far as IMS issues, 997.1 3.6L or 3.8L engines with the later style IMS Bearing (3.6L engines# 05-6950745 forward & 3.8L Engines# 68509790 forward) have had very minor % of IMS failures.
The later larger 997.1 single-row bearing was designed to have a higher load-bearing capacity than the earlier 997.1 IMS Bearing.

And as far as Bore Scoring, as I have read & been following over the years, the "S" engines are more prone to Bore Scoring than the 3.6L and the later 997.2 engine is in fact prone to Bore Scoring.as well but % are lower.
However as these cars attain higher miles, I believe the % of Bore Scoring may turn out to be on the same level as the 997.1 engines but that's only a guess..
Bottom line when you PPI your car get the Bore Scoring Inspection no matter how painful the extra $350-$400.