So I am wondering if it is acceptable to bypass the cooling circuit on the aos if there is no chance of freezing. It would be useful to pressure-test the coolant circuit on the AOS. This seems that it would be simple- take the two hoses that go to the AOS, put a pressure gauge on one hose, cap the other and charge the circuit with air. The AOS has to be able to hold a considerable amount of pressure. A leak in the diaphragm would be easy to detect.

What I am seeing in my coolant is more of a goop and not the milkshake that everyone speaks about. I am starting with the simplest items, AOS (which is new), then oil cooler and working my way to the dreaded cracked head...

You may recall that I suddenly had intermix-like symptoms immediately after changing my AOS.

 

Yes there was a write up recently on RT where someone did what you describe regarding the pressure test.

I would also retrace your AOS connections, it does have connections for both oil and coolant as you know and they must go in exactly the right places. Although it would difficult/hard to imagine "plugging in" an oil connector into the coolant hose and vice/versa.

And as it is only a $100 item and not terribly difficult to replace (just a minor pain), perhaps get a warranty replacement and swap it out again, they can have cracks and could have just been bad from the get go.

More common intermix culprits are oil cooler and cracked heads.

FYI I dug up the post from a very knowledgeable person regarding the operation of AOS and intermix possibility (I won't reveal his exact occupation but I can say he has a close relationship with Porsche):

http://www.renntech.org/forums/topic...s/#entry210285

edit: I also edited my post that you quoted for accuracy, I'm not 100% on this but the intermix residue probably totally unlikely from AOS (read above post for explanation). i.e.: AOS failure, oil in coolant = nope / coolant in oil = possible.

 

I agree wholeheartedly. However I also don't hear about engines from other automotive marques grenading in the frequency and the mileage of what has come up for discussion unless an engine had been very mistreated through neglect or intentional abuse, I can't remember the last time I heard about engine self-destructing with basic everyday cars from ANY marque with ANY recognizable pattern, let alone the failures with IMSB, cracked cylinder head, and chain tensioners which seemed to have shown to have a real potential of occurring with the 1999-2008 engines.

As for the band-aid analogy, that is really not a fair comparison, I’d like to think it’s more akin to getting a better helmet when biking because the older, lesser quality helmet might crack and cause me injury if I wiped out one day, especially if some, however few, of these helmets have cracked under similar situations.

And yes at that point I WILL sleep better at night.

And in the helmet scenario, the particular helmet manufacturer would likely have been forced to recall the less quality helmets, but we won't go there!

This I agree, however no amount of marketing/hype for the supply of goods or service will be worth anything if there is no demand.

Agree too, which is why I still don't have an iPhone, or iPad, but do have an iPod Touch because it fits my needs. I also still haven't gone to get the IMSB changed yet after owning the car for a year now, not because I do or don't believe it is a problem, but rather it does not seem to be a problem which is wide-spread with high occurance rate to warrant my decision to replace it immediately, time will tell if I will "pay" for this decision.

This I agree too!!

 

On this point we are in total agreement! Your avatar has highlighted the most important points of this entire thread!

 

Thanks very much for your input, DB's996! I never thought my question to Jake would get an answer, given how the thread took a tangent at the moment I posted, so your input is a bonus, indeed: Merci beaucoup!
The likelihood of running a double row in my C2 makes me feel much more comfortable, but they can blow too as it happened to an acquaintance of mine on his way from Ontario to NY in a 99C4, which resulted in a very expensive tow, back to Canada, and a replacement engine, etc.

If I may, did you ever have a chance to look at the old one?
If so, did it need to be replaced, although I'm sure you are happy it is?
Finally, what was your approx mileage, then?
Cheers,
Martin

 

My '99 had a dual row too, felt and looked good. Car has 320,000km.

 

My 01 also had a dual row which looked good but replaced with the L&N dual row. Feel like this is the best set up to have.

 

So far I have only heard of one instance of double row IMSB failure. Any one else?

 

I just lost a stock 996 motor last week and I know the pain ( in the pocket) it sucks, I finally got it looking amazing, full GT3 look with o.e. parts including Gt3 wheels to boot, not to mention a $10,000 paint job, roll bar, 5 point and a new Sparco race seat for those "used to be fun " track days.
My quest is now, to find out about putting a GT3 motor in a "99 base modle with cable throttle???
Anyone with any ideas ???

 

I just went through a similar situation with my 2002 996. Engine ended up needing a complete re-build. I shopped around a LOT and also spoke to Jake at Flat 6. They wanted about $18K to do the rebuild. I have some good racer friends in Southern California who recommended Vision Motorsports in Laguna Hills. Dwain there did the rebuild, including a new RMS bearing and other "mods" for around $12K. Fantastic work, impeccable attention to detail and a really upstanding guy who took the time to talk me through all my angst. I highly recommend him, even though I live in GA ans had to ship the motor across the country. (By the way, Flat 6 said their next open date to start working on my motor was sometime in MARCH, 2013! I couldn't wait that long...

 

I also have a 2002 that suffered IMS failure a few months ago. I am still having a hard time coming to grips with the cost. Flat 6 was about 7-8 months out at the time. Ended up biting the bullet and going with a "new"(and ridiculously expensive) Porsche factory crate engine. Feels good to have a two year warranty but now I have the "upgraded" bearing that cannot be replaced without engine tear down, and the initial quotes I have received range from $9k-$15k. So did Porsche take a flawed design and compound the problem by now making the bearing inaccessible? I will not be around to find out. I just don't have it in me (or in my checking acct) to pony up ANOTHER five digit payment to keep a $25k car on the road. I guess it's time start shopping for my next 911...this time with a dry sump as well, so I can kill two 996 birds with one stone.

 

VERY interesting. Intricate failures on 996 cars....good to get such great repsonses. Way to go, all.

 

Update to my original thread start. This update has nothing to do with any IMSB issues as my car had none.

After a few weeks, my 996 is home from Flat 6 Innovations and running beautifully. Jake Raby and his team performed some maintenance items that needed to be done to include: RMS, clutch, water pump, IMS retrofit with spin on filter and magnetic plug, AOS, etc.

Prior to sending my car to Flat 6 I did my due diligence and researched them...as I would with any company that I plan on doing business with. I chose to send my car there based on my research and findings. I am glad I did. My experience with them was nothing short of uber professional. I want to thank Jake Raby, Dean and all of the Flat 6 team for their unbelievable honesty and integrity, not to mention their mechanical skills. I now have a car that I have full faith in and can enjoy for many years to come.

I am sure that I will be accused by some of being a poster boy for Flat 6 Innovations and part of their wicked and evil marketing scheme. Not the case. When I am treated by a company with unparalled honesty, professionalism and communication, I will sing their praises. Contrary ,if I had been treated differently and shafted so to speak by Flat 6, I would post that as well.

Our cars are expensive to maintain so it is paramount that you do your own research when you need repairs. Don't take my word for it. I am simply one extremely happy customer and would say so if I wasn't.

Thanks again Jake and Flat 6! Happy motoring to all.

 

Not by me. Jake's work is an important contribution to the community and the board, but his tone can get tiresome. People just have to remember two things: One, he is selling something, for a profit, and this is not a crime. And two, he spends every waking moment with broken Porsches and their angry owners. That's going to skew anyone's perspective. We just have to filter for that.

An important reminder. The low cost of buying one makes people forget that these are still low volume, partially hand-assembled cars built by a struggling company. When a manufacturer doesn't do enough volume to fully develop a product before it goes on sale, the cost gets passed on to the owners. I think my car, which has been trouble free, currently costs me 15% of its value per year for routine maintenance and insurance. That's life with an aging European sports car.

 

Well said, Gator!