Petza914

It's interesting that there are quite a few 08s but not a single 09 or a 10 even though the 08-10 Turbos are the same engine, aren't they? Also interesting that the 955 failures are more prevalent in the NA engines, but the 957s are in the Turbo engines.

Interested to see if the trends change at all as more responses come in.

TomF

There were two sub contractors for the MY 2008 (USA) 4.8 engine. They changed the cylinder honing process early in the MY 2009 4.8 run. As I have said before, I would expect the 2008 CTT to have a lot more failures than others. It would be interesting to find out if there is a way to determine the source of a 2008-2009 (early) 4.8 engine... If there is a correlation between subcontractor and failures, this could offer those with the other subcontractor's block a bit of piece of mind.

I for one am surprised about the high rate of failures shown so far in the survey and I was way off with my earlier estimates.

Cheers,
Tom

TomF

Here is the list from the TSB of engines through 2014 that have the newer structurally honed cylinders. Note that my 2008 that had a failure was not one of these, and smooth-honed.

"Only engines with structurally honed cylinder liners are used in vehicles as of the shown engine numbers:
References:
92AAH1, 92AAI1, 92AAL1, 970110, 970111, 970120, 970121, 970410, 970411, 970420, 970421, 970430, 970431, 970440, 970441, 970450, 970451, 9PAAH1, 9PAAH7, 9PAAI1, 9PAAL1, 9PAAL7, 9PAAN1, 9PAAS1
Model year as of 2008"

Cheers,
Tom

Petza914

Great info. Where do I find the engine designation on my motor to compare to this list for my 09 Turbo S? I have a COA for all of my Porsches - is it on there?

I think your subcontractor info might help explain the 08s to 09/10 failure difference.

jdh2550

It's a part of the VIN - starting at position 7. Mine is 9P28LA - which isn't in the good list. Probably means my bores are made of tissue paper? (joke! just kidding. Me worried? Nah...)

p.s. I just filled in the survey.

Petza914

My VIN says 9P59LA for those characters, but us sn 09 so....

TomF

Take a look at the build sheet in your trunk. My 09 CTTS has the 9PAAN1 engine, so it falls on the list of structurally-honed cylinders, which is the later process. The car was assembled in 8/08. Don't panic and keep in mind that there is nothing definitive about the theory linking the honing process to the failures. It is simply a hunch.

I really would like to know if any of the listed failures in the survey have engines that fall on this list of engines with structurally-honed cylinders. As I said above, my 2008 did not.

Cheers,
Tom

Petza914

Will do and let you know. Where is that in the trunk?

TomF

In the spare tire/subwoofer compartment, on the driver's side at the very back. It may be missing as it is just paper.

Cheers,
Tom

Petza914

Label was still there. My 09 TTS is also a 9PAAN1. Build date from the door sticker is 07/08.

Thanks.

TomF

This is incorrect. The VIN number does not contain the engine number. My 2009 CTTS has the 9PAAN1 engine, but the middle of the VIN is 9P29LA which is not the engine.

Cheers,
Tom

Petza914

+1 - also confirmed by my post exchange below with TomF. Engine # not the same as VIN digits.

deilenberger

FWIW - latest results (98 vehicles reporting) 1 2010 is reported and no failure. A number of 2009's are reported and as far as I can see - no failures.

A PDF of the results so far:

pvanosta

I looked at the sticker in the spare tire compartment. It says 9PAAI1.
My understanding is that this engine code is on the list of 'good ones' in this thread. And yet I had fatal scoring at 63,000 miles. (Euro 2007 CTT)...

deilenberger

Based on our survey and information on when the honing process for the cylinder bores changed - your 2007 Euro was still within the risk class. The bore change happened late 2009 as far as I can tell. It's notable that we've received no reports of bore failure for 2010 and newer V8's.