Intermix/Cracked head repair

I thought I would provide an update on the solution to the intermix/cracked head problem on my 2000 996. For those of you who haven�t seen the previous threads, last September, 8 months after the expiration of my EasyCare extended warranty my car developed an intermix problem, with significant amounts of oil in the coolant and coolant in the oil. Initially I tried to change the oil and top off the coolant to see how long before the intermix reoccurred, but it seemed to happen immediately (although some of this might have been residual contaminated fluids in the engine and cooling system).Therefore it seemed that a new engine would be required, and with the economy limiting the budget I parked the car for the winter. This spring I started work on the car, first checking the oil cooler for any problems, but quickly determined that this was not the source of the intermix. Then I dropped the engine and begin disassembling it. Soon I found the crack in cylinder head 1-3, cylinder 1 at the inner exhaust valve seat, which you can see in the photo above. This seems to be a very common problem, and the most common area for cracks in the heads of M96 engines. Now I considered four or five alternatives, a remanufactured/rebuilt engine, a used engine, a used cylinder head, a new cylinder head or fixing the crack in the head I had. The replacement of the engines was out of my budget. Porsche now wants over $12,000 plus a core for a remanufactured engine (this is through Sunset or Suncoast, the list is much higher), and only warranties the engine if it is installed by a dealer. I wanted to stay married so that option was quickly ruled out. Looked at some sources for rebuilt engines, but they seem to be $7,000+ and somewhat of an unknown quantity. Used engines seem to be $5,000+ and are also an unknown quantity. I checked out the cost of a new head, which list for about $2,700, and Sunset and Suncoast were about $2,400, and the 1-3 heads were in Germany so over a month away. The parts department at Suncoast did lead me to a dealer in the Chicago area who appears to have the only new 1-3 head in the states, and would let it go for approx $2,400. But I found out that Porsche only warranties the head if it is installed by a dealer. Seemed like a lot of money for a head without any warranty. So I scratched that alternative. Next I tried to find a good used 1-3 head, but they are very scarce. Several wreckers had 4-6 heads but no 1-3 heads. Found a set of heads through a member in Florida at an incredible price, but I asked the member, who is a Porsche tech to check the heads for cracks. He said he had never seen a cracked head but would gladly check the heads. A little penetrating dye showed that the 1-3 head was cracked a cylinder #1, inner exhaust valve seat. Found another set, but when they were checked 1-3 was also cracked. Do we see a pattern here? Found another set in NY, but they were from an independent/Ebay seller who could not tell if they were cracked. He said he would refunds the money if they were cracked, but we could not agree on a price, and I was worried on getting the money back. Cracks in the 1-3 heads seem to be far too common. I spoke to Jake Raby and he told me that in a 10 day period they tore down 5 engines for big bore upgrades, and 4 had cracked heads, although only one had developed an intermix problem. But we all know that cracks don�t get better, and it is probably only a matter of time until the other cracked heads would lead to problems. Jake said he would certainly not use a cracked head so he was sitting on the engines until a solution could be found. So I decided to have the head repaired. Kind of figured that with so many heads cracking in the same area maybe a repaired head would actually be stronger. Sent the Head to Costa Mesa R&D, where they have experience with repairing these heads. Here is a picture of the repaired head, it is supposed to be delivered to me on Friday and I hope to be back on the road in the next week or so. The cost of the repair was $503, including a valve job and drilling out a frozen bolt on the cam sensor and putting in a coil, plus about $30 shipping in each direction. I am keeping my fingers crossed that this is the solution to my problem. Wish me luck!

Wow! I hope this works out, thanks for the update.

Wow! Wish you luck and hoping you succeed. You may have just found a new business for yourself.

Let me know how this ends up.. That is a very critical area for repair and it appears that they did a very good job. I can't ever risk a repair like this, so even though we have the capabilities to make the same repair I have held off on doing this for Customer's heads to date. I may take the cracked heads we have,repair them and then put them on a used core and punish the hell out of it and overheat it and see if the repair holds in a harsh environment with a failure being induced. Glad to see that you are making progress.. Call me if you need anything during reassembly.

How is this kind of repair accomplished? Is there some way to ensure that the entire crack has been filled? I'm just thinking that if the entire defect isn't sealed that you'll still have a propogation point for a future crack. Great job on pursuing an alternative and keeping the community up to date on your progress!

Hope it works for ya doug. usualy a repair like that would involve drilling each end of the crack and then welding and grinding, looks like a fantastic job to me though.

Looks great! Best of luck. Please keep us updated.

When I originally called John Edwards at Costa Mesa R&D I told him I had a cracked head on my 996. Before I even had to chance to say much more he basically said "oh ya, at the inner exhaust valve seat on cylinder #1, happens all the time." So he knew exactly where it was cracked before I told him and said he had fixed many of them in the past. Appraently they cut out a significant amount of metal in the area and weld in new metal, then machine it as required. He said that he had lots of repaired heads out in the field running in cars. I asked if he had ever had one recrack. He said yes, but never in the area of the repair, always somewhere else. With the number of cracked heads out there it seems that there is some defect in either the design or the manufacturing process. This is one of the reasons I was reluctant to buy a new head. alot of money and if Porsche hasn't changed the casting/process what are the odds of the new head cracking. And when Porsche said they would not warranty a new head unless it was installed by a dealer the choice was amde for me, no new head. Based on my experience and search for a head it seems to me that there are probably alot of cars with cracked heads that have not yet caused a leak, and some of them may never do so, but others are ticking bombs.

Good luck with this one. I have had very good luck over the years with repairs on cracked heads. I see it as a logical, cost-effective, high-probability-of-success solution.

Nice to know that there is a reasonably priced way to fix this as opposed to replacing the engine. Thanks for the research and great work!

Wow, sounds like a great way to save $12k! Assuming if something like that happens on my engine, and I had to pay a mechanic to tear down the engine and send the cracked head to Costa Mesa, it would still be reasonable compared to replacing the engine, I bet?

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Can't wait to see if this solves this. Great work and keep us updated.

great job on researching this particular problem... this will help alot of folks out in the future. Please keep us posted.

I wish you the BEST of luck and hope this works for all of us. You may have saved the Rennlist Community thousands from your research. Thank You! Your posting and pictures have been invaluable.

These cracks are only happening on earlier models... right? (2001 and earlier?)

I am in the same boat myself with 99 C2. Intermix. About to drop engine and disassemble. Will start with bank 1-3!

NONE of the modes of engine failure are limited to certain years or models. We see everything fail across the board- If its an M96 it has 15 different modes of failure that can bring it to it's knees and of those only two have symptoms before "it happens". We repaired a seriously screwed up head last week.. I will put them on a mule engine in a few days and the punishment will begin, so will the overheating and I'll do my best to force it to fail...

Could you give us a list of the fifteen and the symptoms of the two ?

I have an article on engine failures that I have been waiting to finish.. The Spring rush is slowing down a bit, so I'll try to get it posted in June. I try to keep this sort of info off of forums because those who deny the issues exist start debates that I don't have time for..

I'm not trying to start a debate, I would like to know what these problems are, I could probably name 5 of them,but if there are more I'd like to know about them,you have much more experience in these than I have. I think this forum is great to get information on these cars to the members. No high performance car/engines are perfect and without problems.

Hi, Thanks for an excellent write-up! I think I am suffering from the same thing, and I have read your threads with great interest. I have emailed the company you used, to find out if they still repair heads. So I figure your car still work, after the repair? I have borrowed an inspection camera, and I hope the resolution will be good enough to see the crack in the cylinder head. I have a rookie question; cylinder #1, is that the front left one in the forward direction of the car? Just so I am looking in the right place.... Thanks, Johan

Sorry to hear about the intermix. I hope you get it sorted.

Johan: What is the year and mileage of your car? Also what are your symptoms ?

Over 13,000 miles since my fix and the engine is still running strong. Not sure about using the camera so see the crack I had unless you are going to pull the plug tube and look in the chase. Then you might see it. But it would not appear in the cylinder. I think most of the time cameras are used to check for cracked cylinder walls. What are the symptoms of your intermix? Oil in Coolant? Coolant in the oil? Any smoke from the exhaust?

Hi Doug, excellent to hear that your engine is still running strong! Here is a thread I started about my intermix problem: https://rennlist.com/forums/996-foru...n-coolant.html 118 k miles, oil in coolant, no coolant in oil, loosing coolant but engine runs excellent. Is there a way to remove the tube from the outside? It seems like there is no other way to get into the cam housing. Any advice? Thanks, Johan

One of these works well for removing the plugs but you have to get the right size and I forget the diameter of the plug tubes. http://www.westmarine.com/webapp/wcs...classNum=10467

Thanks! I think I have one of these laying around. So, I can pull them out from the outside without permanently damaging them? I might need to move the car to get the engine out, and I would prefer to be able to start it without all the oil pouring out... Regards, Johan

Yes you can remove the tubes safely without damaging anything. They are just plastic tubes If you damage one they are really inexpensive, like a few dollars each. But don't damage them so much that the plastic breaks off into the engine, then you'll have to remove the cam cover to get the debris out. It owuld be really hard to damage them though unless you poked a hole in one which would take a drill or some considerable force. Often times the two rubber o rings on the spark tube are worn and should be replaced, however if you are tearing the engine down you could always do that later. Don't start the car without the tubes in otherwise you'll have a big mess on your hands. There are plenty of threads here and elsewhere about how to replace the spark plug tubes. I suggest you spend a minute or two with the search feature.

Hey Doug, I joined this forum because of the same issue/thread u posted. I have a 1999 911 in beautiful condition and I got the intermix blues. Sucks because I lost hope until I read your thread. Both mechanics I asked said total rebuild is necessary. Hoping I can just get the heads repaired like you did. Any additional advice? Or just tell mechanic to try and get the heads repaired by your place, Mesa?

Costa Mesa R&D, John Edwards. However there are many places doing the head repairs now. In 2008/2009 it was not common. First you have to see what the problem is, but it is probably a cracked head.

Thanks Doug. I really appreciate your help. I'm going to talk to my mechanic to confirm the problem. He's telling me it will cost $1,500 to take apart the engine to sufficiently diagnose the issue so, not sure if that's a fair price. Hope the issue is the same as what your car had and that we can do the same fix. really love this car and want to hold on to it...

great post and glad you were able to repair the head - *what is your guess on shop time to tear down the engine, R&R head? i'm guessing 15hrs?

Doug, Thank you for your posts, they are a constant source of tremendous help. I am in the middle of doing the same work on my 2000 Cab with an intermix problem I noticed this past November. I am planning on calling John Edwards and his crew at Costa Mesa R&D when I get to that point, but I was wondering if anyone has experience with shops in Arizona that can do the head repair (assuming I need it...) along with a valve job.

People ship engine parts to John Edwards from all over. He was sending a block to Australia one time I was there. The guy is a genius. But don't try to interrogate him or impress him with your Internet knowledge.he has no time and less patience with fools. He does not need your business but you probably do need him! His prices are very reasonable and I have never heard a bad word against his work. I have used him for years with flawless results . He knows evrybody in the machining/engine rebuild business . He even wrote 'the book' on it with Sunnen.

Doug thank you for your info very helpful. I too had intermix problem after 130k on my 996. Decided to pull engine and was expecting cracked head or d-chunk in cylinder. I got cracked passenger side head with a small fee zero plug blown out. Crack is on upper side. See pic. Do any members know of a machine shop that can do similar repair in SF bay area. I am in San Jose. Thank you for the forum & members , gave me the courage to jump in head first into the repair.

^^ Uhh - info on the Daytona covered with junk..?

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Yes, Daytona from Roberts Motors Tennessee. One of the last 2 he sold before Ferrari shut him down. A project for later on. Doner is a 78 L82 vette that I traded a 70 911-T for 18 years ago. Seamed like a good idea at the time.

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I'm struggling to get in touch with John, mailbox/email are full and haven't had any luck getting an answer with the number listed on the site. Do you have any other suggestions on where I can get the work done?

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I'd try to find some engine builders in your area and then see who they recommend for a machine shop. Although tricky, these types of repair go on all the time for other brands and makes of engines.

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Hello Friend, Please tell me how is going the cylinder head after repair. I have the same crack in cylinder 6 and going to repair it. Kind Regards, Alex

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Thank You for searching before posting Alex. I don't think Dharn is on here much anymore but I know his head repair was sucessful. As for Costa Mesa R&D I believe they are still in business but John Edwards died about 4 years ago. The best place to have Porsche head work done is Hoffman Automotive Machine.

Is there any preventative stuff to prevent this or just happens for no reason? Cold starts in cold weather places, red lining often, not red lining often, other?

Alex14002, I've just recently gone through the cracked cylinder head issue with my 99' C2 Cabriolet, and can confirm Byprodriver's response to you with regard to Hoffman Automotive Machine in Atlanta. Len Hoffman was a pleasure to work with at a highly anxious moment in my Porsche journey. He did a fantastic job at a very reasonable price, and I was super pleased with the result. I was very apprehensive about shipping the head off to Atlanta from New Jersey, but he made it smooth as butter with precise packaging instructions on his web-site, even provided me with the shipping label, just had to drop the box off at UPS! The car now runs as it should, smooth power and rock steady engine temperature, plus I learned a lot about the engine and cooling system which I hope enables me to avoid this issue in the future on both my 996 and Boxster. Argeo, your best preventative is to stay on top of the cooling system! Make sure your coolant reservoir doesn't have a pin-hole leak (that's what happened to me) and closely monitor your coolant level (that's where I dropped the ball), the condition of your hoses, water pump, radiators and coolant itself. Maybe even consider a low-temperature thermostat, although the benefits are debatable. Ultimately, the cracked head experience was a major pain-in-the-a**, but also strangely rewarding because I was able to resurrect the car so cheaply and gave me the feeling of "beating the system" which I dig!

These cars are getting old. Expansion tanks and water pumps need to be changed out due to age, as we know that a failure with one of these can cause engine damage. We put a new expansion tank in every car we put an engine as we lost a new engine due to failure of an expansion tank that pressure tested ok. There are lots of plastic components on the engines and on these cars that will not age gracefully and as we identify them, they need to be added to the items we replace as preventative maintenance. For example, AOS vent tubes and oil fill tubes are cracked on almost every car that comes in and causes a small vacuum leak that leads to enrichment of the engine and can contribute to cylinder scoring. That's just one example.