Mick The Kraken

(previous text removed for sounding whiny)

1analguy

So...you figure that Porsche designed a great car, but when it came to the cooling system, they had a brain fart and put in the wrong thermostat?

I know, right? This is just one more reason that I'm looking at CPO cars, and will be getting a PPI. I just hope I can find one that hasn't been "improved" like this...

Luxter

Geez,
Read this before you folks post about 160F T-stat:

http://www.pistonheads.com/gassing/t...+scoring&mid=0

Guys, don't reinvent the wheel. Someone far more skilled and talented did it for you.
Cheers,
Luke

1analguy

OK, interesting reading. The conjecture of that post is that localized cavitation or stalled coolant flow resulting in coolant flashing into steam is resulting in localized cylinder damage. I wonder how many of the engines exhibiting this type of cylinder failure also have undamaged pump impellers? If the number is really low, then the coolant flow route would need some attention. If the number is high, then that would raise another issue altogether. I bet someone at Porsche knows the answer.

So, basically, Porsche has in fact released for sale an engine that has improper or inadequate coolant flow in certain areas. For a company that prides itself (and rightly so) on its long history of success in endurance racing to commit such a blunder is not easy for me to accept...and yet something is causing those cylinder failures. After all, there is the IMS issue in the previous engine. Hmmm...

If Porsche really did drop the ball in this engine's cooling development, then I must return to the question that I posed in post #27. Why haven't more (any?) owners tried that waterless coolant? It has such a high boiling point that the type of failure discussed above would probably be much less likely to occur. I just noticed that Evans, the maker of the waterless coolant, has an ad on page 106 of the March print issue of "911 & Porsche World" magazine. It claims the stuff has been "tested and approved by Porsche specialists" such as RPM Technik and Hartech (the same Hartech that wrote your link article?). The science on the stuff does sound quite promising.

Luxter

I will ask Baz directly about the waterless coolant. Agree with you that it sounds promising. Unfortunately he doesn't contribute to RL.
Cheers,
Luke

Mick The Kraken

Thanks for the ribbing, Anus. I guess I'm going to have to give Pelican Parts a call and ask them why the hell they're marketing this BS:

http://www.pelicanparts.com/techarti...eplacement.htm

http://www.pelicanparts.com/catalog/..._pg1.htm#item2

USMC_DS1

As consumers we can only speculate what the engineers and bean counters at Porsche intended and ultimately compromised on when the product went to market. Regardless we can try to understand the nature of the beast and accommodate any shortfall observed in the field after manufacturing. It's very difficult... well costly for Porsche to address an issue after the fact. IMHO Porsche likely intended to engineer an engine with few if any issues up to 100K miles(limits of CPO warranty) but there is nothing like field testing(release for public use) to stress the engine in ways they had not anticipated. Even so called "built proof" engines have their gremlins. Here's another coolant related issue with the Merger engine: https://rennlist.com/forums/10390370-post1.html

I've read the hartech report previously and these coolant flash points in theory occur when the coolant has not fully warmed up to operating temp and the stock t-stat has not open fully... or basically the initial period of the drive when the car is warming up. One way to address this is to warm up the car properly/slowly by keeping the RPM's(more importantly workload) in the low range and then only after getting the engine oil up to operating temp should the engine be worked hard. For example, consider the typically morning commute... driver starts up the car and immediately jumps into traffic on their way to work on time. Some will accelerate to posted speed limits well before the engine temps are at operating(~175*F to 200*F) and the t-stat has not fully opened. Now consider a car at the track... it's warmed up and does a few warm up laps prior to pushing the car to it's limits and t-stat has fully opened. Hartech reports that an unusual number of gently driven engines suffer from this type of coolant flash related failures - d-cunk, cracked heads, scored cylinder linings, etc. IMHO the low temp t-stat can help address this initial start up/warm up issue but it's really up to the driver to allow the car to properly warm up before driving it hard. I take a longer route through the neighborhood each time I drive the car. Adds ~5 minutes and 3 miles to the commute but my oil temp is typically between 175*F(winter) and 200*F(summer) before I jump on to our 60 mph hwy. I know that I'm only a sample of one so not enough of a statistical data point to make it theory but this method is working for me. My '08 C2S has 64K miles on it... Blackstone provides me with a clean bill of engine health after every 3k oil change. And to deal with the TX heat I've added a 3rd rad, FVD extended oil pan, switched to Motul Xcess approved oil, flush my coolant, and replaced my WP preemptively. I hope to keep my Carrera running well beyond 100K miles so a bit of TLC is cheap in comparison to a new engine.

PelicanParts.com

Hi Mick - I'm happy to address any questions you have about the thermostat options we offer or you may call us directly 888.280.7799.

Thank you
Mark/Pelican Parts

Mick The Kraken

Mark -

I literally just logged in with the intention of editing my post, as I thought it came off all wrong. I was being sarcastic. I've read plenty about the pros (and cons) of the low temperature thermostat and thought it made sense to go ahead and install one. I have no beef with you guys, the part or the end result. That said, I appreciate you reaching out.

Cheers, man.

- Mick

1analguy

No problem, Crack. As far as Pelican, they're selling because people are buying.



It looks like you're doing everything that can be done. As a potential owner, this problem scares me just as much as the IMS issue. How's the record of the 9A1 on this cooling issue? Is it exhibiting the same problem at the same rate as the earlier engine?

Call me old fashioned, but I have always winced when hearing of a mass-produced aluminum engine with no iron cylinder sleeves. While I understand the science behind the various metallurgical and coating-based alternatives that have been/are being employed, I can't help feeling that the minor weight savings involved are just not worth the risk. Iron sleeves have probably saved many engines in borderline circumstances such as those described here, and they would certainly fatten the acceptable localized coolant temperature operating range of any engine, including this one.

Luxter

Actually Nikasil is a better choice and has been working well in all Mezger engines for many years.
I still believe that the Millers nano technology oils can substantially reduce (if not eliminate) a risk of IMSB failure and likely reduce cylinder bore scoring. In fact Baz at Hartech recommends Millers CFS 10W-50 NT (yes 50) in all water cooled 996/7 engines to increase oil film strength between piston and cylinder wall.
He also highly recommends low temp T-stat. In fact all (or most) non 996/7 engines are equipped with lower temp t-stats.

Bottom line, top notch condition of your cooling system is paramount to the longevity of your 996/7 engine. There simply is no room for error, in particular in 3.8L Carrera S engines.

1analguy

What about the 9A1 engine in the 997.2s and 991s? Is it also included in the cylinder bore "watch" group?

Luxter

Gen. 2 offers closed deck design, so that will help with preventing bores going oval.
The Lokasil, piston and piston coating combination unfortunately remains the same as Gen. 1 cars.
The IMSB is gone.
DFI presents intake deposit issues and HP fuel pump issues.
Some improvements between Gen. 1 and 2. Still not as bullet proof as Mezgers.

USMC_DS1

+1... sums it up well.

DGrayling

According to page 6 of the Porsche 2009 "Technik Introduction" for all 911 Carrera models available from Suncoast, the crankcase of the 2009 Carrera engine is made entirely of Alusil. Alusil is quite different from Locasil per the below reference.

Quoted from :
http://wardsauto.com/news-amp-analys...s-strong-ideas

"Alusil: The engine block is fashioned from high-silicon content aluminum alloy. The block undergoes initial machining, then, similar to Nikasil, is dipped in an acidic bath that etches away the aluminum on the bore surfaces, exposing the durable-wearing silicon."

"Lokasil: Promoted largely by casting-kahuna Kolbenschimdt Pierburg AG, Lokasil is a "sacrificial" bore liner comprised of silicon fibers in a binding that, when inserted into the block mold, burns out the fibers, leaving the high-content silicon surface directly in the bores."

I was also pleased to read that the crankshaft is drop forged, and the connecting rods and pistons are forged as well on the 997.2 Carrera models.