Serious Engine Problem
- Thread starter AndrewEllinas
- Start date
stevesnaz
New member
Baz,
I am currently researching 996s with a view to purchasing a 2002-04 model after the summer; I'm away with work until then!! I was initially drawn to the C4S, but am now considering spending the extra money to get a Turbo?? Hence joining this forum to start finding out as much as possible about them.
I have read through your guides and found them very informative - thank you. I may have missed it, but I get the impression that the Turbos do not have as many issues for a number of reasons, but one being the lower temp thermostat - is that correct?
Out of interest, how many Turbos, compared with C4Ss, do you have in with the described issue? As you suggest, I presume one of the more cost effective methods of reducing the chance of it occurring is to fit a lower temp thermostat - how much roughly does that cost?
Many thanks
Steve
I am currently researching 996s with a view to purchasing a 2002-04 model after the summer; I'm away with work until then!! I was initially drawn to the C4S, but am now considering spending the extra money to get a Turbo?? Hence joining this forum to start finding out as much as possible about them.
I have read through your guides and found them very informative - thank you. I may have missed it, but I get the impression that the Turbos do not have as many issues for a number of reasons, but one being the lower temp thermostat - is that correct?
Out of interest, how many Turbos, compared with C4Ss, do you have in with the described issue? As you suggest, I presume one of the more cost effective methods of reducing the chance of it occurring is to fit a lower temp thermostat - how much roughly does that cost?
Many thanks
Steve
Welcome Steve!
The Turbo uses a completely different engine to the naturally aspirated cars. It is much more robust, although it also has it's little foibles, like turbo wastegate actuators, but the crankcase, cylinders and heads are considered fairly bullet proof. I have heard of timing chain problems, but they seem to be incredibly rare.
The Turbo uses a completely different engine to the naturally aspirated cars. It is much more robust, although it also has it's little foibles, like turbo wastegate actuators, but the crankcase, cylinders and heads are considered fairly bullet proof. I have heard of timing chain problems, but they seem to be incredibly rare.
stevesnaz
New member
Thanks Richard.
I've always longed after a Turbo, but thought they'd always be out of my price range. I may have got it wrong, but looking through the classifieds (Auto Trader, Pistonheads etc), it would appear that a 996 Turbo of roughly equivalent age and mileage is approx £5,000 - £7,000 more than a C4S...please tell me if I am off.
As many people say, you only ever hear of the things that go wrong, and not about all the people who have had no serious issues. But still, when forking out that kind of money on a second hand car you don't want it to blow up in your face 3 months after you've bought it!!!
Clearly, when I get round to testing later on in the year I'll get a better idea of the difference between the two driving styles. Any other advice would be greatly appreciated.
Until then I'll just keep researching and following the list prices.
Regards
Steve
PS. Is there a price at which people think the used 996s (specifically the Turbo and C4S) will settle at?
I've always longed after a Turbo, but thought they'd always be out of my price range. I may have got it wrong, but looking through the classifieds (Auto Trader, Pistonheads etc), it would appear that a 996 Turbo of roughly equivalent age and mileage is approx £5,000 - £7,000 more than a C4S...please tell me if I am off.
As many people say, you only ever hear of the things that go wrong, and not about all the people who have had no serious issues. But still, when forking out that kind of money on a second hand car you don't want it to blow up in your face 3 months after you've bought it!!!
Clearly, when I get round to testing later on in the year I'll get a better idea of the difference between the two driving styles. Any other advice would be greatly appreciated.
Until then I'll just keep researching and following the list prices.
Regards
Steve
PS. Is there a price at which people think the used 996s (specifically the Turbo and C4S) will settle at?
For early C4Ss and Turbos there is probably less in price difference than you say. Best bet is to drive both before you decide. I'll wager it would be the Turbo though! Both will depreciate, so don't fool yourself, but the Turbo will likely be slightly less (IMHO) as it will be on a slightly flatter part of the depreciation curve.
The Turbo will probably be slightly more expensive to run, in terms of servicing and maintenance, but cheaper on insurance. It also depends on your use. As a weekend toy the Turbo will always be a bit more of an occasion, but if you do a lot of town driving the C4S might be slightly easier to live with - not that the Turbo is difficult. (Again, IMHO).
Enjoy your research and hunt, which is all part of the fun.
The Turbo will probably be slightly more expensive to run, in terms of servicing and maintenance, but cheaper on insurance. It also depends on your use. As a weekend toy the Turbo will always be a bit more of an occasion, but if you do a lot of town driving the C4S might be slightly easier to live with - not that the Turbo is difficult. (Again, IMHO).
Enjoy your research and hunt, which is all part of the fun.
thirteeneast
New member
Careful, when I looked at turbo's in the entry level for Turbo World.
There used and abused.
There used and abused.
Have i read this correct that a Turbo is cheaper on insurance than a Carrera4s.I would very much like to upgrade to a turbo from my c4s if i can use that for a lever with my better half that i am going to save money on insurance then i am half way there.
Kind regards Brian
Kind regards Brian
unclewinks
New member
I was quoted £46.00 more for a gen 1 turbo if that helps
If you look through the 'ultimate' insurance thread, you will find a few instances of the Turbo being cheaper to insure. There have been quite a few posts on Pistonheads too. I think it is most likely due to claims history, but all it takes is a phone call to your insurer to find out, or do a comparethemeerkat.
For those of you that did wade through our section 5 you might be interested to know that GT4 (911.uk) explained how to programme the air con unit to read the coolant temperature and it shows it running about 10 degrees higher than the dash board instrument (exactly as we stated and as our tests revealed).
Baz
Baz
CONCLUSION
The Internet has thrown up a useful confirmation of our findings when a contributor called "GT4" showed how to read the coolant temperature by another system by re-setting the existing digital air con control unit on the pre face lift 996's.
The result confirmed that our own test readings (that showed higher engine coolant temperature readings than the dash board temperature gauge) were right and showed some other interesting facts (that we had also noticed) that add weight to our general conclusion that the engines can run too hot in some circumstances in the cylinder/piston face area.
You will remember (if you read section 5 of our buyers guide) that instead of 100% of the coolant passing each cylinder to cool it "" only about 1.5% to 4% passes each individual cylinder and then mixes with the majority of the coolant that goes through the cylinder head before travelling on a relatively long journey back to the radiator and even later reaching the thermostat and back inside the engine again.
This means that if there is a sudden temperature rise inside the engine (as a result of suddenly driving much faster) it is the cylinder walls that will try and transfer this heat first (because the coolant in the cylinder head is far less effective) and because the coolant in the cylinder area is travelling relatively slowly - that temperature rise will be higher. The coolant from the cylinders then mixes with about 80% of the coolant going through the head (the temperature of which will not yet be affected) "" so the temperature of the resulting mixture will be only slightly elevated as it travels back to the radiator (where it is then cooled) before even reaching the thermostat. The result must be a system that results in much higher immediate cylinder wall temperatures and much hotter pistons because it reacts much more slowly to dissipate that sudden increase in cylinder temperature than more traditional engine designs.
Now the change in cylinder head gasket design has made that balance different in the 3.4 Cayman, 3.6 and 3.8 engines by about 50% - or put another way "" the amount of coolant (as a proportion of the rest going through the cylinder heads) has been reduced in those engines compared to a 3.4 engine "" by about half "" less through the block and more through the head.
This must mean that the temperature rise it has to handle is higher, the proportion of it mixing with the coolant coming out of the cylinder head is less and the resulting mixture going on to the radiator is cooler "" thus creating a further response delay in quickly bringing those temperatures down again (because the thermostat can only react to the whole coolant mix temperature and not the rise just in the cylinder area).
Now if we go back to looking at the difference in the actual coolant temperature readings (between the dash board gauge and either the air con digital signal or our test gauges) "" we find that whereas they rise from cold almost together "" once the dash board gauge reaches about 80 degrees it becomes very slow to read any sudden rises (that the other instruments pick up immediately) and starts to lag behind the true reading as the temperature rises further.
It means that owners don't realise that during some dramatic changes in driving "" temperatures are rising and falling very quickly and to high maximums "" and bearing in mind that this rise came about from a very small amount (that was in the cylinder block) mixing with the cooler majority that is in the head "" when we see a sudden rise of 10 degrees C in the mixed temperature (using the digital or test gauges) "" the rise in the small amount of cylinder coolant temperature must be many times higher than that and certainly could be in that area of boiling and creating air bubble screening 9all of which our tests confirmed).
Now the problem pistons have a PTFE type coating (which some 3.4's have and some don't but has not been a problem in 3.4's) that has always delaminated on the pistons that have not seized - in engines that have scored bores.
So our conclusion still is that the change in the head gasket design has altered the coolant flow ratios and speeds resulting in higher cylinder wall temperatures while the pistons are transmitting higher cylinder wall loads and the consequence is either that the additional load and heat gradually de-laminates the coating that then jams against the pistons rings (causing scoring) or the increased load/unit piston face area is too much for the oil film to support.
This justifies the changes we make to the coolant flow when we rebuild the engines and also verifies the benefit that fitting a lower temperature thermostat to engines that are presently Ok will have "" by compensating for the slow reaction time of the cooling system (because it then starts off at a lower temperature) and allows the slow reacting cooling system to recover back to a sensible running temperature before it has risen far enough to cause damage.
Baz
The Internet has thrown up a useful confirmation of our findings when a contributor called "GT4" showed how to read the coolant temperature by another system by re-setting the existing digital air con control unit on the pre face lift 996's.
The result confirmed that our own test readings (that showed higher engine coolant temperature readings than the dash board temperature gauge) were right and showed some other interesting facts (that we had also noticed) that add weight to our general conclusion that the engines can run too hot in some circumstances in the cylinder/piston face area.
You will remember (if you read section 5 of our buyers guide) that instead of 100% of the coolant passing each cylinder to cool it "" only about 1.5% to 4% passes each individual cylinder and then mixes with the majority of the coolant that goes through the cylinder head before travelling on a relatively long journey back to the radiator and even later reaching the thermostat and back inside the engine again.
This means that if there is a sudden temperature rise inside the engine (as a result of suddenly driving much faster) it is the cylinder walls that will try and transfer this heat first (because the coolant in the cylinder head is far less effective) and because the coolant in the cylinder area is travelling relatively slowly - that temperature rise will be higher. The coolant from the cylinders then mixes with about 80% of the coolant going through the head (the temperature of which will not yet be affected) "" so the temperature of the resulting mixture will be only slightly elevated as it travels back to the radiator (where it is then cooled) before even reaching the thermostat. The result must be a system that results in much higher immediate cylinder wall temperatures and much hotter pistons because it reacts much more slowly to dissipate that sudden increase in cylinder temperature than more traditional engine designs.
Now the change in cylinder head gasket design has made that balance different in the 3.4 Cayman, 3.6 and 3.8 engines by about 50% - or put another way "" the amount of coolant (as a proportion of the rest going through the cylinder heads) has been reduced in those engines compared to a 3.4 engine "" by about half "" less through the block and more through the head.
This must mean that the temperature rise it has to handle is higher, the proportion of it mixing with the coolant coming out of the cylinder head is less and the resulting mixture going on to the radiator is cooler "" thus creating a further response delay in quickly bringing those temperatures down again (because the thermostat can only react to the whole coolant mix temperature and not the rise just in the cylinder area).
Now if we go back to looking at the difference in the actual coolant temperature readings (between the dash board gauge and either the air con digital signal or our test gauges) "" we find that whereas they rise from cold almost together "" once the dash board gauge reaches about 80 degrees it becomes very slow to read any sudden rises (that the other instruments pick up immediately) and starts to lag behind the true reading as the temperature rises further.
It means that owners don't realise that during some dramatic changes in driving "" temperatures are rising and falling very quickly and to high maximums "" and bearing in mind that this rise came about from a very small amount (that was in the cylinder block) mixing with the cooler majority that is in the head "" when we see a sudden rise of 10 degrees C in the mixed temperature (using the digital or test gauges) "" the rise in the small amount of cylinder coolant temperature must be many times higher than that and certainly could be in that area of boiling and creating air bubble screening 9all of which our tests confirmed).
Now the problem pistons have a PTFE type coating (which some 3.4's have and some don't but has not been a problem in 3.4's) that has always delaminated on the pistons that have not seized - in engines that have scored bores.
So our conclusion still is that the change in the head gasket design has altered the coolant flow ratios and speeds resulting in higher cylinder wall temperatures while the pistons are transmitting higher cylinder wall loads and the consequence is either that the additional load and heat gradually de-laminates the coating that then jams against the pistons rings (causing scoring) or the increased load/unit piston face area is too much for the oil film to support.
This justifies the changes we make to the coolant flow when we rebuild the engines and also verifies the benefit that fitting a lower temperature thermostat to engines that are presently Ok will have "" by compensating for the slow reaction time of the cooling system (because it then starts off at a lower temperature) and allows the slow reacting cooling system to recover back to a sensible running temperature before it has risen far enough to cause damage.
Baz
Excellent work Baz. Thanks for your valuable contributions.
OP, how did this work out for you?
The reason give by Porsche GB for not making a goodwill payment to me when the engine in my 996 failed prematurely was that the car had never had an extended warranty. Given that you had paid for 7/8 years of additional cover which was in force until a couple of weeks prior to the incident, I was expecting to see you posting that all had been resolved to your satisfaction?
AndrewEllinas
New member
Well, Christmas and the New Year slowed everything down but I've just heard from Porsche Hatfield that Porsche UK are unwilling to make any contribution towards the cost of the repair. I have to say that has surprised me.
I am going to contact Customer Services myself and write to the MD, but I'm not very hopeful.
If I can't get Porsche to help out - which are the best independents for me to go consider using?
I am going to contact Customer Services myself and write to the MD, but I'm not very hopeful.
If I can't get Porsche to help out - which are the best independents for me to go consider using?
chris gibbs
PCGB Member
Hartech
Link:-
http://www.hartech.org/
I am sure many others on this forum will support this suggestion.
Link:-
http://www.hartech.org/
I am sure many others on this forum will support this suggestion.
AndrewEllinas
New member
Thank you. They are top of my list.
Has anyone actually had experience of them carrying out significant work on their car, like an engine rebuild?
Has anyone actually had experience of them carrying out significant work on their car, like an engine rebuild?
DivineE
New member
Just so you know, bazhart (the technical post above) is Hartech. Plus yes I've had an engine strip done there and they are very good. You should see their workshop and machine rooms, its a lovely to know we have a setup like that working to keep Porsches on the road and even nicer that its in the UK for a change! Usually when you see these things they come from across the sea.
There was a big article on Hartech in 911 Porsche World last year (can't remember which month sorry), but if you get a chance to see it they give a nice discription of the place. Plus some good photos from behind the scenes.
Hi Andrew
I wouldn't waste your time contacting Porsche GB -the customer service department are unhelpful and rude - unless of course you happen to be a perpetual buyer of new Porsche's.
My recent experience with them over my sports exhaust failure ( document here on the forum ) was not very pleasant. I also wrote to the MD, Andy Goss, with all the details etc and despite knowing him personally for over 10 years I never heard a words from him. How disappointing that was.
They even questioned my loyalty to the brand because I had not had an extended warranty! Anyone in the club who knows me would realise how insulting and hurtful that was to me.
You claim, like mine and everyone else is judged on a matrix of information and if it doesn't fit the model then tough - you are on your own.
I would love to be proved wrong in your case, so the best of luck to you.
AndrewEllinas
New member
[FONT=arial"]Dear Peter,
Thank you for your post.
The really disappointing thing about all this is that Porsche have known that there is an inherent issue with the IMS in the 996 engine since the start but have decided to deny it.
That says a lot about their loyalty to us, their customers. They want us to be loyal and passionate about the brand but are not prepared to respond back in a similar manner. That's upsetting.
I knew about it from this forum shortly after I bought the car (my posts are recorded) and that's why I continued to renew the Extended Warranty year after year.
The fact that the MD, Andy Goss, did not reply to your letter is, in all honesty, unforgivable. I didn't realise that people were able to do that in these "˜connected times'.
My lawyer friend suggests a class action, joining all IMS suffers together, to take Porsche to court to force them to admit their liability for an inherent fault. I doubt whether it would be successful as Porsche would have so much to lose that they would throw a lot of money at top lawyers to defend it.
I will write to Andy Goss and will let you know if I get a reply.
Regards
Andrew![[FONT=verdana,geneva"]](/forum/styles/default/pcgb/space.gif ". [FONT=verdana,geneva\"]")
Thank you for your post.
The really disappointing thing about all this is that Porsche have known that there is an inherent issue with the IMS in the 996 engine since the start but have decided to deny it.
That says a lot about their loyalty to us, their customers. They want us to be loyal and passionate about the brand but are not prepared to respond back in a similar manner. That's upsetting.
I knew about it from this forum shortly after I bought the car (my posts are recorded) and that's why I continued to renew the Extended Warranty year after year.
The fact that the MD, Andy Goss, did not reply to your letter is, in all honesty, unforgivable. I didn't realise that people were able to do that in these "˜connected times'.
My lawyer friend suggests a class action, joining all IMS suffers together, to take Porsche to court to force them to admit their liability for an inherent fault. I doubt whether it would be successful as Porsche would have so much to lose that they would throw a lot of money at top lawyers to defend it.
I will write to Andy Goss and will let you know if I get a reply.
Regards
Andrew
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