996 head core plugs

Can anyone tell me if they have heard about core plugs coming out of the cylinder head of a 996 3.4 engine and what is the cause. This has happened to my enigine on a run a couple of weeks ago and the only saving grace was that I was going slow at the time or the damage would have been a lot more than I have now. The garage has said that the core plug in the head between cylinder 5 and 6 came out dumping the water in the the oil separator and then back into the engine intake side filling number 6 cylinder with water which hydro locked the piston on the upward stroke. result is the con rod for nimber 6 is bent like a banana and a couple more may be damaged also not the full extent of the damage has been given yet. The engine block has been sent to Hartech for measuring of the bores to see if new liners are needed but the initial problem has me worried because if they replace this core plug could it happen again to another one. Has anyone had or heard of any similar problems with the 996 engine Thanks Peter hopper

core plug wow !!! never heard of that one... I would also be very worried about the crank having twisted ...Hartech will check it no doubt but would be surprised if it was not..very

Which garage has diagnosed this?

more news The block was sent to Hartech and they looked at it and found that some of the liners would need replaced so I went for 6 plus 4 new pistons and new rings for all the pistons. The heads were also sent to Hartech and a core was glued in place and then the heads pressure tested with no leaks. The heads will now be overhauled after the core plug ports have been treaded to take screw in core plugs which will stop this problem happening again. Hartech do this with the racing engines they build so I think that they must have found a similar problem with race cars shedding core plugs in the past. They have also kindly supplied a con rod because porsche would only sell these in a set of 6 at the price of £170 each and as only one was bent then this was quite a saving and very nice of them to help. The rework should be done in a week or so and then the parts sent back to the garage in Newcastle, which is D & G Motor Engineers at Silver link in Newcastle. Dean and Gary two very good engineers who worked for Porsche Newcastle and have set up themselves and doing very well. The saving grace was that at the time it happened I was not going to fast around 40 to 50 when all hell broke loose with the dash lighting up like Christmas and a cloud of smoke James Bond would have been proud of. I nipped it into neutral and pulled over and called the breakdown service, who came and took the car to D&G for investigation. The core plug had come out and water went into the oil/water separator and then burst the diaphragm and into the induction depositing the water into number 6 cylinder and the piston coming up tried to compress the water which resulted in the engine hydrolocking. The oil pump was also damaged breaking the end of the pump off with the sudden stop and I will know the full extent when they gat the block back and look at the IMS and bearing plus new clutch and anything else that needs to be renewed like shells and other things. It looks like ti is going to be over £8000 at the moment but not sure what the final bill will be at this time.

Glad to hear it on the road to recovery, amazing what can happen with a simple part failing.

core plugs about 3K of that will be pistons and rings did you know that Woosner(German) now make a piston set for the 3.4 & 3.6 M96 engine , much better than the Mahle units and £800 for a set of 6 complete with rings, pins and circlips , that's about 4k less than Porsche Woosner part number is K9472DA (3.4) contact www.forged-pistons.co.uk have used a set and they are great no problems at all :hand: :hand: :hand:

Re: core plugs We would not fit wossner but would fit mahle or Capricorn to give a different view.

On the mend Thanks for all the info but Hatech have done all the work on the block and heads and not sure what they have used but as they build race engines I'm quite confident that the job will be a good one. I think that this is the best I can do to make sure that the core plugs do not fail again but to be honest this should not happen on this engine especially as it only has 60,000 miles and the car is 14 years old. Not a very good advert for a performance engine which is reputed to be a good all round car for the road and it was not being driven hard at the time and shudder to think what could have happened. Knowing porsche they would not even look at this as their problem but something must be wrong or why would the race engines have screw in core plugs unless this has happened to the race engines. You would not expect this on a road engine. I would not be teling any friends to buy a porsche and would look at a jag or Audi R8.

Head core plug fail Just stripped my 3.4 and also found a core plug loose inside the cam chamber It's the one between 5-6 again Symptoms include coolant in sump and milkshake in AOS etc. This is a project car so engine being stripped as no known history other than arrived with no coolant and no oil showing in header tank or on Dipstick

Re: On the mend I get you are probably upset about this and it has been expensive. But its a 14 year old car, an old car by anyone standards, and a rare failure - first (and second) I've heard of it in over 5 years on the forum. Its probably just a random failure and you were unlucky. Maybe it was put in wonky who knows. I'm sure similar things will be happening to the odd 14 year old R8. And I would run a country mile from a 14 year old jag v8..... Time to enjoy the M96 for what it is - really one of the best performance car engines ever made.

Re: On the mend Sorry to hear you have had issues - some of the horror stories on here do worry me. I realise for every horror story there are hundreds who dont post, as their engine is fine, but regardless an £8k bill on a £15k car would be a real blow for me (and most people). Sadly, seems lots of cars have their issues..I have a friend with a V10 R8 - he has had loads of gearbox issues. He is part of an R8 forum where there are people with similar experiences......however again, they may be in a small minority (but I know it cost him £10k)....

I had one fail in my turbo. Was a bloody nightmare situation but at lease due to my intake setup my oil tank now vents to atmosphere so the coolant / oil mixture came out the tank breather rather than feeding back in to the intake. Had it gone in to the intake it would have made a big mess.