Has your 996 or 997 engine had a major rebuild?
Poll: Has your 996 or 997 engine had a major rebuild?
Total Members Polled: 867
Discussion
With the greatest respect - read reports from people with standard thermostats and listen to the observations of others and you will find that buffered or not the standard thermostat fluctuates more than our low temperature thermostat (have you tried both yourself - I have).
I have also test driven two cars with 4 different thermostat settings and fitted with remote accurate temperature sensors fitted in strategic parts of the engine - recording true temperatures for different conditions and driving (as part of our engine repair development).
I had also read others who have fitted ours and found the same and was just reafirming what they said after my first drive in my own rebuilt 3.8 it was more stable than before - that's all.
But thank you for trying to rubbish my research and development and point out what an idiot I must be on such a trivial issue and for simply posting my findings for the benefit of other readers.
Baz
I have also test driven two cars with 4 different thermostat settings and fitted with remote accurate temperature sensors fitted in strategic parts of the engine - recording true temperatures for different conditions and driving (as part of our engine repair development).
I had also read others who have fitted ours and found the same and was just reafirming what they said after my first drive in my own rebuilt 3.8 it was more stable than before - that's all.
But thank you for trying to rubbish my research and development and point out what an idiot I must be on such a trivial issue and for simply posting my findings for the benefit of other readers.
Baz
FYI Cmoose - Hartech is the person who told _us_ about the various ways temperature can be measured in the engine, and how the standard gauge differs from the actual temperatures.
This is, in fact, how he arrived at the need for a lower temp thermostat, and discovered the lack of proper cooling past certain cylinders. It's obvious from his posts that he's spent a great deal of time getting accurate temperature readings too as part of his research into the bore-scoring (etc) issues. In essence then, he knows more about the temperatures inside these engines than most people except perhaps for the odd technician in the Porsche engine department (who it seems were told to keep their findings quiet and not rock the boat).
So when people tell you about engine temperatures you can generally ignore them (because they will be referring to the standard gauge with has been made 'comforting', but when Baz says something about them he means the real engine temperature and you can guarantee it is accurate.
This is, in fact, how he arrived at the need for a lower temp thermostat, and discovered the lack of proper cooling past certain cylinders. It's obvious from his posts that he's spent a great deal of time getting accurate temperature readings too as part of his research into the bore-scoring (etc) issues. In essence then, he knows more about the temperatures inside these engines than most people except perhaps for the odd technician in the Porsche engine department (who it seems were told to keep their findings quiet and not rock the boat).
So when people tell you about engine temperatures you can generally ignore them (because they will be referring to the standard gauge with has been made 'comforting', but when Baz says something about them he means the real engine temperature and you can guarantee it is accurate.
I don't agree Cablemoose - I have seen the temperature vary a lot during testing and driving customer cars (even though the guauge is buffered) and so have the various respondants of these topics.
The important point for owners to realise is that IF (as I believe) one of the problems in these engines is localised bubbling inside the cylinders through running too hot - that will result in temperature fluctuations - even though the thermostat is set for a constant temperature. This is because bubbling temporarily overheats the local coolant and when it mixes back with the rest it creates a sudden temperature blip in the system both from the bubbling and the fact that that area of the block is getting hotter while there is no coolant adjacent to it and that it then takes a little while for the thermostat to respond to and it usually over reacts etc which can be seen on the guauge.
The fact that this thermostat of ours runs a lower temperature (and has other designed in response speeds) - reduces that incidence and results in less of these fluctuations.
The other important point I was trying to make (but perhaps didn't explain enough this time but have done before) is that our tests show that the dashboard guauge reads reasonably accurately up to about 80 to 82 degrees and then as temperatures rise - understates the actual temperature - eventually by quite a large amount. The fact mine stayed exactly @ 80 is therefore a demonstration of a stable running temperature (since at that position it is still responding reasonably accurately and is not gradually understating the actual temperature - when it is showing a smaller temperature range than it is actually varying in.
I think my comment was thereforer significant (as it seems to have been to others).
The reason I get annoyed about comments like yours (and I know I should keep it too myself) is that whereas I was merely pointing out what I observed (and therefore what is true and I think relevant) you make a statement that the only reason my guauge stayed still was because the guauge was buffered - which is not true - therefore your post could be misleading to others who do not know any better and therefore it needs correcting (IMHO). Regardless of the argument - you do not know why or how my guauge works or what I observed - but I do know how hundreds of engines respond and after numerous changes to thermostats and coolant flow.
I would have been less responsive if you had said something along the lines that - "perhaps the fact it was stable had something to do with the fact it is buffered" and then it is not a statement of fact (in your opinion) but a reasonable comment open to correction if neccessary.
I guess I am also having a hard day at the office with too much to do - so may have been less professional in my reaction than I try to usually be and if so - sorry.
Baz
The important point for owners to realise is that IF (as I believe) one of the problems in these engines is localised bubbling inside the cylinders through running too hot - that will result in temperature fluctuations - even though the thermostat is set for a constant temperature. This is because bubbling temporarily overheats the local coolant and when it mixes back with the rest it creates a sudden temperature blip in the system both from the bubbling and the fact that that area of the block is getting hotter while there is no coolant adjacent to it and that it then takes a little while for the thermostat to respond to and it usually over reacts etc which can be seen on the guauge.
The fact that this thermostat of ours runs a lower temperature (and has other designed in response speeds) - reduces that incidence and results in less of these fluctuations.
The other important point I was trying to make (but perhaps didn't explain enough this time but have done before) is that our tests show that the dashboard guauge reads reasonably accurately up to about 80 to 82 degrees and then as temperatures rise - understates the actual temperature - eventually by quite a large amount. The fact mine stayed exactly @ 80 is therefore a demonstration of a stable running temperature (since at that position it is still responding reasonably accurately and is not gradually understating the actual temperature - when it is showing a smaller temperature range than it is actually varying in.
I think my comment was thereforer significant (as it seems to have been to others).
The reason I get annoyed about comments like yours (and I know I should keep it too myself) is that whereas I was merely pointing out what I observed (and therefore what is true and I think relevant) you make a statement that the only reason my guauge stayed still was because the guauge was buffered - which is not true - therefore your post could be misleading to others who do not know any better and therefore it needs correcting (IMHO). Regardless of the argument - you do not know why or how my guauge works or what I observed - but I do know how hundreds of engines respond and after numerous changes to thermostats and coolant flow.
I would have been less responsive if you had said something along the lines that - "perhaps the fact it was stable had something to do with the fact it is buffered" and then it is not a statement of fact (in your opinion) but a reasonable comment open to correction if neccessary.
I guess I am also having a hard day at the office with too much to do - so may have been less professional in my reaction than I try to usually be and if so - sorry.
Baz
No you are saying I am wrong just because it doesn't make sense to you - which is actually rather arrogant and rather unscientific. Basically – you state that - all my research and actual testing and conclusions and actual observations are wrong – just because “it doesn’t make sense to you” (who have done nothing comparable to test or observed the results).
I have tested these cars and these engines with accurate temperature gauges fitted into the engine compartments and various feeds (you have not) and I can assure you that with the right thermostat - driven as I did (don't forget running in so although up to say 80mph - not with aggressive acceleration and on a motorway or doodling around the lake district) the gauge (and the temperatures it related to) were more stable than normal.
It isn't really relevant if that makes sense to you or not until you similarly test in much the same way and find that wrong (which you would not).
I have noticed this stability before with our thermostats (in fact they were designed specially to achieve that) but I have not had many miles in a 3.8 before and now I have – I have been able to report – something that I am very pleased about and that I think is significant (as these are the most vulnerable engines in the range) that they work just as well (in fact better than I expected) in different speeds and conditions in that engine as well.
The reason shows up how much ignorance there is about coolant systems. I cannot remember if it was you I had a run in about this recently - but whoever it was stated that the thermostat stays fully open all the time once the car is hot - and this is also completely wrong and shows a complete lack of understanding of the system.
Look - the thermostat is a flow control device - that moves in relation to temperature but controls coolant flow. As long as the radiator system is reasonably balanced to the car and the conditions are not too hot for the system to work - then this is how it works.
The engine gets up to temperature and the thermostat starts to open slowly and the flow starts to the radiators.
If they are designed right it makes relatively little difference to the cooling rate if the speed of the engine changes – the load on the engine changes or the air conditions vary. This is because with good design one thing tends to cancel out another and the cooling remains well balanced. Higher speeds means more load and coolant heat soak but increased speed increases air flow and better cooling etc. one thing seems to balance out the other.
The main thing that influences the cooling is the difference in the temperatures and flow rates of the air and the coolant – creating a temperature difference and volume/time. The greater the temperature difference or flow rate the more potential cooling can take place. Just like with cooling down something hot under a tap – if the cold water flow is increased it cools quicker and if the water is colder it also cools quicker (and visa versa).
So if the air is very cold – it has the potential to can quicker or if it is very hot – the potential to cool less effectively – so what manages to keep the temperature stable? – the variation of the coolant flow (volume/time).
If the coolant is moving more volume and it re-circulates more often the radiators can reduce the temperature more often. However this also means that they coolant travels through the radiator more quickly – so it has less time in there to remove heat. This is where the design needs to be well balanced – if it is things like air temperature and car speed (hence airflow speed) have less of an influence on the cooling potential of the system than if the radiators are too big or too small or the airflow is more variable through the radiator than the road speed on its own would affect. If you doubt this just consider that you all know the engine will overheat if the pump fails or the radiator inlet is blocked.
All these variations are then finely controlled by the thermostat. If the coolant temperature is getting too hot (because you are driving hard or stuck in traffic going slow) – it opens a little more and increases the coolant flow and hence more quickly cools the engine. If the engine is getting too cool – it closes a little and slows the coolant flow – allowing the engine to heat up again.
How well all this works is dependent on the speed of the thermostat opening and closing and the design of the thermostat valve head. The valve head has to translate the increase in flow to balance the increase in cooling potential of the system – so the reaction of the change is both quick enough (but not too quick) and stable. If for example a very small opening makes a huge difference to the coolant flow rate the temperature would quickly fall and then the thermostat would close quickly again but slow the coolant too much and you would have coolant temperatures fluctuating up and down. Similarly if the thermostat itself opened to quickly or slowly – it would always be chasing the ideal temperature you want the system to run at. The speed it opens (and how far it moves/degree of temperature rise) is dependent on the expansion tube size, volume and what it is filled with while the valve head size influences the relative increase and decrease in flow to the linear movement of the tube at different temperatures.
Balancing the thermostat operating speed and the resulting flow rate change through its valve head with the engine type, and use, water pump speed, ambient conditions anticipated etc – all lead to a system that would be stable but anything out of balance would result in fluctuations. The grater distance of the radiators from the engine is also an influence since it also builds in a delay in response time for the cooler coolant to return to the thermostat and influence its position - so - IMHO - needs faster response time to temperature changes.
You only have to read other similar posts on this subject to realise the standard thermostat results in such variations – yet it was clear to us that the system as a whole has the potential to cool OK (or it would not work in very hot Countries).
We therefore set out not only to provide a thermostat that would allow the engine to run cooler but also one that would make it more stable. Having achieved that I think it was relevant and informative to post my experiences of it in my 3.8 and as this is relevant to the reliability of the range – I think it is both misleading and unhelpful to state that this must be wrong “just because it doesn’t make sense to you” and that the only reason my gauge was stable is because it is buffered.
Frankly I don’t really understand why people with less experience than others seem to be so positive on the Internet when they state – sort of categorically – that something is right or something (or someone) else is wrong – as if it is an absolute fact of science and everyone therefore should only listen to them. I mean – it doesn’t really bother me (I usually know what I am talking about when it comes to engines) but it does worry me that others believe them and are therefore completely misinformed – so that is why – in such circumstances – I feel obliged to correct any mistakes.
Personally I don’t like putting others down and I don’t like the fact it also makes me seem arrogant and opinionated. Here at Hartech we operate totally opposite and employees at all levels are positively encourages to make decisions and ask questions – as we all try to come up with the best solutions jointly. We are not an autocratic organisation and I am not an autocrat – but the result of our approach means that more of us really understand things and the combined ability we have when we put our heads together is awesome.
The basis for this philosophy is that whatever the theory or anyone else says – does it work – if it does – even if we don’t understand why – that is always the first test completed and we then try to work out how and why. We have three graduates, ex-main dealers technicians etc and design and manufacture more engine parts and solutions than anyone else for this range of engines – with an excellent customer satisfaction rate and reliable rebuilds – so I feel that – when we observe something and inform others about it – I would not expect any to state we are wrong – just because THEY DON’T UNDERSTAND IT. I think in these situations a little more respect and a tad more modesty may indeed straighten out most misunderstandings without needing to feel defensive and recriminatory afterwards.
Of course the coolant temperature on its way to the radiator - has to vary in order to adjust the thermostat position on its way back and all temperature gauges are buffered to stop them swinging from side to side as things change quickly - but the standard thermostats still reveal that the engine temperature is rising and falling slower than the buffered gause is showing while with ours - the speed of the thermostat and that of the buffered gauge are well matched and therefore this does actually reflect better temperature control.
Finally - don't forget we have also altered the coolant flow rates inside the engine slightly to better balance the temperatures inside and that of course also contributes to better temperature stability at different driving engine loads and heats when the coolant mixes back together again on its way back to the radiators.
Baz
I have tested these cars and these engines with accurate temperature gauges fitted into the engine compartments and various feeds (you have not) and I can assure you that with the right thermostat - driven as I did (don't forget running in so although up to say 80mph - not with aggressive acceleration and on a motorway or doodling around the lake district) the gauge (and the temperatures it related to) were more stable than normal.
It isn't really relevant if that makes sense to you or not until you similarly test in much the same way and find that wrong (which you would not).
I have noticed this stability before with our thermostats (in fact they were designed specially to achieve that) but I have not had many miles in a 3.8 before and now I have – I have been able to report – something that I am very pleased about and that I think is significant (as these are the most vulnerable engines in the range) that they work just as well (in fact better than I expected) in different speeds and conditions in that engine as well.
The reason shows up how much ignorance there is about coolant systems. I cannot remember if it was you I had a run in about this recently - but whoever it was stated that the thermostat stays fully open all the time once the car is hot - and this is also completely wrong and shows a complete lack of understanding of the system.
Look - the thermostat is a flow control device - that moves in relation to temperature but controls coolant flow. As long as the radiator system is reasonably balanced to the car and the conditions are not too hot for the system to work - then this is how it works.
The engine gets up to temperature and the thermostat starts to open slowly and the flow starts to the radiators.
If they are designed right it makes relatively little difference to the cooling rate if the speed of the engine changes – the load on the engine changes or the air conditions vary. This is because with good design one thing tends to cancel out another and the cooling remains well balanced. Higher speeds means more load and coolant heat soak but increased speed increases air flow and better cooling etc. one thing seems to balance out the other.
The main thing that influences the cooling is the difference in the temperatures and flow rates of the air and the coolant – creating a temperature difference and volume/time. The greater the temperature difference or flow rate the more potential cooling can take place. Just like with cooling down something hot under a tap – if the cold water flow is increased it cools quicker and if the water is colder it also cools quicker (and visa versa).
So if the air is very cold – it has the potential to can quicker or if it is very hot – the potential to cool less effectively – so what manages to keep the temperature stable? – the variation of the coolant flow (volume/time).
If the coolant is moving more volume and it re-circulates more often the radiators can reduce the temperature more often. However this also means that they coolant travels through the radiator more quickly – so it has less time in there to remove heat. This is where the design needs to be well balanced – if it is things like air temperature and car speed (hence airflow speed) have less of an influence on the cooling potential of the system than if the radiators are too big or too small or the airflow is more variable through the radiator than the road speed on its own would affect. If you doubt this just consider that you all know the engine will overheat if the pump fails or the radiator inlet is blocked.
All these variations are then finely controlled by the thermostat. If the coolant temperature is getting too hot (because you are driving hard or stuck in traffic going slow) – it opens a little more and increases the coolant flow and hence more quickly cools the engine. If the engine is getting too cool – it closes a little and slows the coolant flow – allowing the engine to heat up again.
How well all this works is dependent on the speed of the thermostat opening and closing and the design of the thermostat valve head. The valve head has to translate the increase in flow to balance the increase in cooling potential of the system – so the reaction of the change is both quick enough (but not too quick) and stable. If for example a very small opening makes a huge difference to the coolant flow rate the temperature would quickly fall and then the thermostat would close quickly again but slow the coolant too much and you would have coolant temperatures fluctuating up and down. Similarly if the thermostat itself opened to quickly or slowly – it would always be chasing the ideal temperature you want the system to run at. The speed it opens (and how far it moves/degree of temperature rise) is dependent on the expansion tube size, volume and what it is filled with while the valve head size influences the relative increase and decrease in flow to the linear movement of the tube at different temperatures.
Balancing the thermostat operating speed and the resulting flow rate change through its valve head with the engine type, and use, water pump speed, ambient conditions anticipated etc – all lead to a system that would be stable but anything out of balance would result in fluctuations. The grater distance of the radiators from the engine is also an influence since it also builds in a delay in response time for the cooler coolant to return to the thermostat and influence its position - so - IMHO - needs faster response time to temperature changes.
You only have to read other similar posts on this subject to realise the standard thermostat results in such variations – yet it was clear to us that the system as a whole has the potential to cool OK (or it would not work in very hot Countries).
We therefore set out not only to provide a thermostat that would allow the engine to run cooler but also one that would make it more stable. Having achieved that I think it was relevant and informative to post my experiences of it in my 3.8 and as this is relevant to the reliability of the range – I think it is both misleading and unhelpful to state that this must be wrong “just because it doesn’t make sense to you” and that the only reason my gauge was stable is because it is buffered.
Frankly I don’t really understand why people with less experience than others seem to be so positive on the Internet when they state – sort of categorically – that something is right or something (or someone) else is wrong – as if it is an absolute fact of science and everyone therefore should only listen to them. I mean – it doesn’t really bother me (I usually know what I am talking about when it comes to engines) but it does worry me that others believe them and are therefore completely misinformed – so that is why – in such circumstances – I feel obliged to correct any mistakes.
Personally I don’t like putting others down and I don’t like the fact it also makes me seem arrogant and opinionated. Here at Hartech we operate totally opposite and employees at all levels are positively encourages to make decisions and ask questions – as we all try to come up with the best solutions jointly. We are not an autocratic organisation and I am not an autocrat – but the result of our approach means that more of us really understand things and the combined ability we have when we put our heads together is awesome.
The basis for this philosophy is that whatever the theory or anyone else says – does it work – if it does – even if we don’t understand why – that is always the first test completed and we then try to work out how and why. We have three graduates, ex-main dealers technicians etc and design and manufacture more engine parts and solutions than anyone else for this range of engines – with an excellent customer satisfaction rate and reliable rebuilds – so I feel that – when we observe something and inform others about it – I would not expect any to state we are wrong – just because THEY DON’T UNDERSTAND IT. I think in these situations a little more respect and a tad more modesty may indeed straighten out most misunderstandings without needing to feel defensive and recriminatory afterwards.
Of course the coolant temperature on its way to the radiator - has to vary in order to adjust the thermostat position on its way back and all temperature gauges are buffered to stop them swinging from side to side as things change quickly - but the standard thermostats still reveal that the engine temperature is rising and falling slower than the buffered gause is showing while with ours - the speed of the thermostat and that of the buffered gauge are well matched and therefore this does actually reflect better temperature control.
Finally - don't forget we have also altered the coolant flow rates inside the engine slightly to better balance the temperatures inside and that of course also contributes to better temperature stability at different driving engine loads and heats when the coolant mixes back together again on its way back to the radiators.
Baz
cmoose: If you don't want Baz to (quite rightly) overreact, don't keep trying to plug your 'You've said this but you're wrong' statement.
Baz and his guys do this for a living.
You have an opinion, backed up with - insofar as I'm aware - precisely no technical knowledge.
If you don't understand the topic, stay off your keyboard.
Baz and his guys do this for a living.
You have an opinion, backed up with - insofar as I'm aware - precisely no technical knowledge.
If you don't understand the topic, stay off your keyboard.
Hi Mr Moose. Suggest you grab one of the alternative stats as I did and pop it in (your engine that is!). Some of the design features that make it better than the std were repported in my post Aug 1, notably the copper body. Copy here:
Baz feedback on your low temp thermostat which I popped in a month ago....
-visually, is a much better better design; copper body, larger diameter so more surface area, hollow bore to thin out the thermal capacity.
-my thermostat housing was a 2003 item and the sealing face was poor with very slight leak so users should consider replacing old housing -I actually circumvented the spend by lapping the face on an oil stone!
-the cooling system bleeds out much easier due to lower opening temp.
-the car now runs at a steady 79 deg C, previously was 88 (measured via climate display). Upon queuing to exit Silverstone in 21c weather for 90 mins with air con on, the engine stayed under 90 deg C all the time!
I still get a temperature increase when driving around town just like described earlier but its a lower increase. Still also have trouble shifting the heat energy build up after slowing down from a motorway run, but again its a lower & slower increase, so great, glad I did it. Still think however that I will look for ways to increase the cooling system power so will be doing some airflow improvement mods on the (2) front radiators and also popping in a fan-on (without air-con) override switch -that is unless anyone knows how to set a lower switch on temperature for the fans, ie 90 deg C instead of 101 deg C or so???
Over & out.
- ************
Baz feedback on your low temp thermostat which I popped in a month ago....
-visually, is a much better better design; copper body, larger diameter so more surface area, hollow bore to thin out the thermal capacity.
-my thermostat housing was a 2003 item and the sealing face was poor with very slight leak so users should consider replacing old housing -I actually circumvented the spend by lapping the face on an oil stone!
-the cooling system bleeds out much easier due to lower opening temp.
-the car now runs at a steady 79 deg C, previously was 88 (measured via climate display). Upon queuing to exit Silverstone in 21c weather for 90 mins with air con on, the engine stayed under 90 deg C all the time!
I still get a temperature increase when driving around town just like described earlier but its a lower increase. Still also have trouble shifting the heat energy build up after slowing down from a motorway run, but again its a lower & slower increase, so great, glad I did it. Still think however that I will look for ways to increase the cooling system power so will be doing some airflow improvement mods on the (2) front radiators and also popping in a fan-on (without air-con) override switch -that is unless anyone knows how to set a lower switch on temperature for the fans, ie 90 deg C instead of 101 deg C or so???
Over & out.
Personally, I think this is bad advertisement for Porsche and Porsche owners. The figures the voting give and other forums provide are only based on those searching for the engine problem on the internet and not every owner. Most Porsche owners will just give the car to a main dealer or specialist. So I clicked no, which shows 110 people have no problems, about 10 have had problems and 36 people wouldn't buy one because there could be problems.
I have recently purchased a 997 C2S and asked the Guildford Center Dealership the question. Response is here - http://www.fastgerman.com/forum/?p=78
Thank you for your recent enquiry. There is some truth in the matter regards Rear Main Oils seals on the 996 model rather than the 997 models, the problem occurred with the pre face lift models thus pre 2001 models. the latter engines more refined and better reliability being the 1st water cooled engines in the 911.
I would not have any concerns regards the 997 model but with there being over 100,000 997s in circulation now and the engine was a development of the previous model of which a similar number were produced. There is no inherent fault with the engines and either model of car should provide the driving enjoyment you desire.
Regards
Stefan Loots
Porsche Specialist
Porsche Centre Guildford
I have recently purchased a 997 C2S and asked the Guildford Center Dealership the question. Response is here - http://www.fastgerman.com/forum/?p=78
Thank you for your recent enquiry. There is some truth in the matter regards Rear Main Oils seals on the 996 model rather than the 997 models, the problem occurred with the pre face lift models thus pre 2001 models. the latter engines more refined and better reliability being the 1st water cooled engines in the 911.
I would not have any concerns regards the 997 model but with there being over 100,000 997s in circulation now and the engine was a development of the previous model of which a similar number were produced. There is no inherent fault with the engines and either model of car should provide the driving enjoyment you desire.
Regards
Stefan Loots
Porsche Specialist
Porsche Centre Guildford
Hi CMoose, interesting point, are you an early Boxster? Later models seem to have better air flow exit route in the wheel arches (which I dont).
Will likely soon try monitoring the engine temp on my BMW to try understand whether the over-temp occurs there as well (and also whether the gauge is un truthfull!)(
Will likely soon try monitoring the engine temp on my BMW to try understand whether the over-temp occurs there as well (and also whether the gauge is un truthfull!)(
fastgerman said:
Personally, I think this is bad advertisement for Porsche and Porsche owners. The figures the voting give and other forums provide are only based on those searching for the engine problem on the internet and not every owner. Most Porsche owners will just give the car to a main dealer or specialist. So I clicked no, which shows 110 people have no problems, about 10 have had problems and 36 people wouldn't buy one because there could be problems.
I have recently purchased a 997 C2S and asked the Guildford Center Dealership the question. Response is here - http://www.fastgerman.com/forum/?p=78
Thank you for your recent enquiry. There is some truth in the matter regards Rear Main Oils seals on the 996 model rather than the 997 models, the problem occurred with the pre face lift models thus pre 2001 models. the latter engines more refined and better reliability being the 1st water cooled engines in the 911.
I would not have any concerns regards the 997 model but with there being over 100,000 997s in circulation now and the engine was a development of the previous model of which a similar number were produced. There is no inherent fault with the engines and either model of car should provide the driving enjoyment you desire.
Regards
Stefan Loots
Porsche Specialist
Porsche Centre Guildford
So the dealer has said "our engines are fine, just one or two niggles with the very early main seals, nothing to worry about chap". Hardly a surprise there. But yet there are still several very well documented common weaknesses with these engines. The only real question is how many actually fail. Certainly enough for it to register loud and clear on any Porsche enthusiast forum and plenty of advertised used cars with replacement or rebuilt engines kicking around.I have recently purchased a 997 C2S and asked the Guildford Center Dealership the question. Response is here - http://www.fastgerman.com/forum/?p=78
Thank you for your recent enquiry. There is some truth in the matter regards Rear Main Oils seals on the 996 model rather than the 997 models, the problem occurred with the pre face lift models thus pre 2001 models. the latter engines more refined and better reliability being the 1st water cooled engines in the 911.
I would not have any concerns regards the 997 model but with there being over 100,000 997s in circulation now and the engine was a development of the previous model of which a similar number were produced. There is no inherent fault with the engines and either model of car should provide the driving enjoyment you desire.
Regards
Stefan Loots
Porsche Specialist
Porsche Centre Guildford
But Cablemoose I didn't say my car was stable in all driving conditions (like towns) or everywhere - I described exactly what journeys I did, how many miles and explained I was driving it for the first time after a rebuild at the factory (so obviously not racing it but running it in). It was a small comment on a fact I observed and that therefore related to my car, my thermostat and the mods we did internally (which - don't forget others cannot do unless it is stripped and rebuilt).
This is the problem I find on the Internet where some people are so anxious to appear knowledgeable they don't read what they are criticising properly and are overly quick to state - "as a matter of scientific fact" that they know better - presumably to elevate their own status.
So much research and thorough testing went into making that thermostat - that I was pleased that my own car showed such stability and low temperatures and - I think - rightly annoyed at your criticism - and right to point out to readers who who not know who to believe - all the relavant technical facts supporting those results. After that they are welcome to make up their own minds.
However I am sorry it backfired on you - but I didn't start it - did I.
If ever anyone thinks I am wrong or need correcting - please don't be shy or frightened about an argument - I am not the source of all knowledge and I know just how much I want to still learn (despite being over 65).
I will also be courteous and respectful to proper discussion - and (as has already been seen) don't mind apologising if I am wrong or been too harsh in my response.
Baz
This is the problem I find on the Internet where some people are so anxious to appear knowledgeable they don't read what they are criticising properly and are overly quick to state - "as a matter of scientific fact" that they know better - presumably to elevate their own status.
So much research and thorough testing went into making that thermostat - that I was pleased that my own car showed such stability and low temperatures and - I think - rightly annoyed at your criticism - and right to point out to readers who who not know who to believe - all the relavant technical facts supporting those results. After that they are welcome to make up their own minds.
However I am sorry it backfired on you - but I didn't start it - did I.
If ever anyone thinks I am wrong or need correcting - please don't be shy or frightened about an argument - I am not the source of all knowledge and I know just how much I want to still learn (despite being over 65).
I will also be courteous and respectful to proper discussion - and (as has already been seen) don't mind apologising if I am wrong or been too harsh in my response.
Baz
anonymous said:
[redacted]
Gotta say this is a tad patronising given the recipient's expert knowledge. I worked as a race engineer in F1 for 18 years and was always amazed at some of the letters armchair enthusiasts would write to us explaining what we were doing wrong and how we could improve! Used to wind me up too sometimes especially the ones on race strategy. Even on garage tours corporate bobble hatters would sometimes make a point of telling us how things worked 
Probably wasn't intended to wind Hartech up in fairness, but I can see why it did!
Or another interpretation of your view is that "you cannot ever be wrong about anything and would never admit to being so even if you realised you were". My gauge stayed where it was because of our thermostat and internal changes and if they had not been in the engine it would have fluctuated a lot and run at a much higher temperature - thank you and good night!
Baz
Baz
anonymous said:
[redacted]
It is yes, but that scenario only happened in your head 
.Enough already - the new thermostat is obviously a big improvement for temperature and stability.
Baz - have you tried one of these thermostats hooked up on the coolant outflow yet? (obviously with the inlet one removed). I'd be interested to know what the effect was re stability of temperatures. TIA
STiG911 said:
cmoose: If you don't want Baz to (quite rightly) overreact, don't keep trying to plug your 'You've said this but you're wrong' statement.
Baz and his guys do this for a living.
You have an opinion, backed up with - insofar as I'm aware - precisely no technical knowledge.
If you don't understand the topic, stay off your keyboard.
You may have a point but let's remember that these flawed engines were designed by highly skilled engineers with massive resources and they got it wrong. Technical knowledge and 'doing it for a living' isn't always a guarantee apparently..... Baz and his guys do this for a living.
You have an opinion, backed up with - insofar as I'm aware - precisely no technical knowledge.
If you don't understand the topic, stay off your keyboard.
I have not tried it yet Globs but will do. One problem is ensuring that the engine coolant heat gets to the thermostat before the internals overheat - otherwise the coolant may boil before the thermostat sees enough heat to open.
I need to analyse the flow paths in the outer housing and work out where to take a byepass feed from that will be easy and simple to utilise.
Baz
I need to analyse the flow paths in the outer housing and work out where to take a byepass feed from that will be easy and simple to utilise.
Baz
s_mcneil said:
aruck said:
Looks like a lot less chance of failure than had worried me previously.
Running at 15.5% so far, I'd say that is massively high..Gassing Station | 911/Carrera GT | Top of Page | What's New | My Stuff