996-997 wet-sump engine reliability: enter your stats here!
Discussion
tonikaram said:
Updated stats:
1 failure, No RMS, 77Km, 3.4
1 failure, 3 RMS, 58Km, 3.6
1 failure, No RMS, 16Km, 3.4
1 failure, No RMS, 41Km, 3.6
1 failure, 1 RMS, 46Km, 3.6
No failure, 1 RMS
No failure, 1 RMS
No failure, 1 RMS
No failure, 1 RMS, 102Km, 3.4
No failure, 1 RMS, 42Km, 3.4
No failure, 1 RMS, 48Km, 3.6
No failure, 1 RMS, 90Km, 3.4
No failure, 3 RMS, 40Km, 3.6
no failure, 1 RMS, 88Km, 3.6
no failure, 1 RMS, 3.6
no failure, 2 RMS, 3.6
no failure, no RMS, 3.4
no failure, no RMS
no failure, no RMS, 18km, 3.6
no failure, 1 RMS, 99Km, 3.4
no failure, no RMS, 8Km, 3.6
no failure, 1 RMS, 29Km, 3.6
no failure, 1 RMS, 29Km, 64km, 3.4
no failure, no RMS, 40Km, 3.6
no failure, no RMS, 48Km, 3.4
no failure, no RMS, 3.4
no failure, no RMS, 32km, 3.4
no failure, 2 RMS, 56Km, 3.6
Out of a total of 28 996's:
- 18%, or 5 cases, have had engine failures at an average of 48,000Km (rather early, but the span is from 16,000 to 77,000Km)
- 61%, or 17 cases, have had RMS. When you have it, you get it on an average of 1.3 times.
From those that specified the engine, 10 3.4s and 11 3.6s participated so far in the survey.
Kay
km..or miles??...I cant see how this can work really. You need to carry out a census over a percentage of the total units in service. You also need to factor in..age..history..milage..owners..type of use...engine type...etc etc. Even having 50 or 100 comments it will not show a true measure of the facts. Sorry!1 failure, No RMS, 77Km, 3.4
1 failure, 3 RMS, 58Km, 3.6
1 failure, No RMS, 16Km, 3.4
1 failure, No RMS, 41Km, 3.6
1 failure, 1 RMS, 46Km, 3.6
No failure, 1 RMS
No failure, 1 RMS
No failure, 1 RMS
No failure, 1 RMS, 102Km, 3.4
No failure, 1 RMS, 42Km, 3.4
No failure, 1 RMS, 48Km, 3.6
No failure, 1 RMS, 90Km, 3.4
No failure, 3 RMS, 40Km, 3.6
no failure, 1 RMS, 88Km, 3.6
no failure, 1 RMS, 3.6
no failure, 2 RMS, 3.6
no failure, no RMS, 3.4
no failure, no RMS
no failure, no RMS, 18km, 3.6
no failure, 1 RMS, 99Km, 3.4
no failure, no RMS, 8Km, 3.6
no failure, 1 RMS, 29Km, 3.6
no failure, 1 RMS, 29Km, 64km, 3.4
no failure, no RMS, 40Km, 3.6
no failure, no RMS, 48Km, 3.4
no failure, no RMS, 3.4
no failure, no RMS, 32km, 3.4
no failure, 2 RMS, 56Km, 3.6
Out of a total of 28 996's:
- 18%, or 5 cases, have had engine failures at an average of 48,000Km (rather early, but the span is from 16,000 to 77,000Km)
- 61%, or 17 cases, have had RMS. When you have it, you get it on an average of 1.3 times.
From those that specified the engine, 10 3.4s and 11 3.6s participated so far in the survey.
Kay
Hi Bcnrml
Most car manufactures will pull a engine off the line and test it to destruction. The ave fig is about every 5000 units this way they can check if there is any recurring faults due to maybe casting slippage or machine tool setup or parts supplied from outside supplliers etc.
When Ford wanted a high performance unit for the Puma they commisioned Yamaha to design it. Before they put it into production they ran it flat out to see how durable it was,After running for 2 weeks solid they gave up and pulled it apart to find it was perfect.
The trouble in getting accurate figs is . On most cars you can go to companies like Warranty Direct and get info on what they continue to breakdown with but 95% of Porsche are on their own scheme.
Also manufactures have different ways of going about fixing problems.
I know Mercedes are very good at carrying out mods when you put the car in for service without owners even knowing. We put a A class in for a A service and the warranty bill came to £2000 due to their be mods to the Trailing arms ,Brake system and new steering column all of which had give us no problems what so ever.
Some companies are more transparent than others.
Most car manufactures will pull a engine off the line and test it to destruction. The ave fig is about every 5000 units this way they can check if there is any recurring faults due to maybe casting slippage or machine tool setup or parts supplied from outside supplliers etc.
When Ford wanted a high performance unit for the Puma they commisioned Yamaha to design it. Before they put it into production they ran it flat out to see how durable it was,After running for 2 weeks solid they gave up and pulled it apart to find it was perfect.
The trouble in getting accurate figs is . On most cars you can go to companies like Warranty Direct and get info on what they continue to breakdown with but 95% of Porsche are on their own scheme.
Also manufactures have different ways of going about fixing problems.
I know Mercedes are very good at carrying out mods when you put the car in for service without owners even knowing. We put a A class in for a A service and the warranty bill came to £2000 due to their be mods to the Trailing arms ,Brake system and new steering column all of which had give us no problems what so ever.
Some companies are more transparent than others.
You have proven the value of the statistics - well done.
As I mentioned on a different posting about 996 engine reliability (I think) the position of the crankshaft relative to the hole that supports the seal is not guaranteed as it is not machined at the same time.
It is clear to us that some seals fail at very low mileages - then continue to fail again and again whereas some seals last up to 100K and never fail.
Although it need special tools and even a vernier or micrometer to check that the seal is in square to the crankshaft (as any tool that pushes the seal in does not neccessarily result in a square position because the rubber that it is made of compresses and so even if it is pushed in with a square tool it can end up out of square and needs checking) - there is nothing anyone can do to correct an out of alignment of the seal position right from the manufacturing and assembly stage.
We have measured around 0.25mm out of alignment (some more - some less) and in my view this is a design/manufacturing tolerance that is unreasonable and wrong - although I would have thought a seal design could be developed that could cope with it. For example a seperate seal carrier that can be located in line and then secured in position or an extension of the original casting that holds the main bearings so it also holds the RMS instead of it being held in a seperate casting that is out of line.
The size of the crank journal and the design and quality of the seal will be the same - so it must be that those that fail the most are simply those that go together with the most out of alignment.
There is also some age related stress relieving of the casing that holds the seal because it is not restrained anywhere near the centre being more like a bell housing - which also contributes to the out of alignment.
In my view this should be an accepted fault always repaired FOC by Porsche and I cannot believe that they have not thought out how to fix it by now.
For example - if the crank carrier was extended and a stub protruded into the cylinder casting holding the seal in the crank carrier and with an o ring between that and the cylinder casting - it would be perfectly OK.
Having made that point - most old Porsche's leak a little oil and you know it is not a serious problem - putting a small amount of top up oil in the engine every few weeks will not affect the reliability of anything else and a small tray left strategically on the garage floor can prevent oil staining.
This and the bearing problem in the intermediate shaft, should have been sorted out years ago.
Baz
As I mentioned on a different posting about 996 engine reliability (I think) the position of the crankshaft relative to the hole that supports the seal is not guaranteed as it is not machined at the same time.
It is clear to us that some seals fail at very low mileages - then continue to fail again and again whereas some seals last up to 100K and never fail.
Although it need special tools and even a vernier or micrometer to check that the seal is in square to the crankshaft (as any tool that pushes the seal in does not neccessarily result in a square position because the rubber that it is made of compresses and so even if it is pushed in with a square tool it can end up out of square and needs checking) - there is nothing anyone can do to correct an out of alignment of the seal position right from the manufacturing and assembly stage.
We have measured around 0.25mm out of alignment (some more - some less) and in my view this is a design/manufacturing tolerance that is unreasonable and wrong - although I would have thought a seal design could be developed that could cope with it. For example a seperate seal carrier that can be located in line and then secured in position or an extension of the original casting that holds the main bearings so it also holds the RMS instead of it being held in a seperate casting that is out of line.
The size of the crank journal and the design and quality of the seal will be the same - so it must be that those that fail the most are simply those that go together with the most out of alignment.
There is also some age related stress relieving of the casing that holds the seal because it is not restrained anywhere near the centre being more like a bell housing - which also contributes to the out of alignment.
In my view this should be an accepted fault always repaired FOC by Porsche and I cannot believe that they have not thought out how to fix it by now.
For example - if the crank carrier was extended and a stub protruded into the cylinder casting holding the seal in the crank carrier and with an o ring between that and the cylinder casting - it would be perfectly OK.
Having made that point - most old Porsche's leak a little oil and you know it is not a serious problem - putting a small amount of top up oil in the engine every few weeks will not affect the reliability of anything else and a small tray left strategically on the garage floor can prevent oil staining.
This and the bearing problem in the intermediate shaft, should have been sorted out years ago.
Baz
9hellheaven said:
tonikaram said:
Updated stats:
Out of a total of 28 996's:
- 18%, or 5 cases, have had engine failures at an average of 48,000Km (rather early, but the span is from 16,000 to 77,000Km)
- 61%, or 17 cases, have had RMS. When you have it, you get it on an average of 1.3 times.
From those that specified the engine, 10 3.4s and 11 3.6s participated so far in the survey.
Kay
km..or miles??...I cant see how this can work really. You need to carry out a census over a percentage of the total units in service. You also need to factor in..age..history..milage..owners..type of use...engine type...etc etc. Even having 50 or 100 comments it will not show a true measure of the facts. Sorry!Out of a total of 28 996's:
- 18%, or 5 cases, have had engine failures at an average of 48,000Km (rather early, but the span is from 16,000 to 77,000Km)
- 61%, or 17 cases, have had RMS. When you have it, you get it on an average of 1.3 times.
From those that specified the engine, 10 3.4s and 11 3.6s participated so far in the survey.
Kay
We cannot hope that this 'survey' is going to be anything like 100% scientifically accurate , but using a bit of common sense does service to the thread.
It does point the finger to the fact that leaky seal syndrome is all too common. But it also brings to the fore (thanks Baz Hart) that this is meerly an inconvenience and is grossly over rated in terms of it's ability to ruin the fantastic experience that is 996 ownership.
The percentage engine failure that we have at the moment , though pointing to the fact that it's happening more than it should , is skewed , and if the mods were to make this thread into a 'sticky' (hint hint), the percentage engine failures would drop. It's only natural that if you've suffered an engine failure you'll be more driven to post on this topic , than if you've had an ultra reliable 996 (which I believe is the case with the vast majority of these cars).
It would also be interesting to see if the percentages differ between pre and post facelift models .. If you're posting , or have posted , would you specify year , model , mileage ??
DAZREN .... STICKY??? 
Dunit said:
Hi Bcnrml
Most car manufactures will pull a engine off the line and test it to destruction. The ave fig is about every 5000 units this way they can check if there is any recurring faults due to maybe casting slippage or machine tool setup or parts supplied from outside supplliers etc.
When Ford wanted a high performance unit for the Puma they commisioned Yamaha to design it. Before they put it into production they ran it flat out to see how durable it was,After running for 2 weeks solid they gave up and pulled it apart to find it was perfect.
The trouble in getting accurate figs is . On most cars you can go to companies like Warranty Direct and get info on what they continue to breakdown with but 95% of Porsche are on their own scheme.
Also manufactures have different ways of going about fixing problems.
I know Mercedes are very good at carrying out mods when you put the car in for service without owners even knowing. We put a A class in for a A service and the warranty bill came to £2000 due to their be mods to the Trailing arms ,Brake system and new steering column all of which had give us no problems what so ever.
Some companies are more transparent than others.
Hi Dunit,Most car manufactures will pull a engine off the line and test it to destruction. The ave fig is about every 5000 units this way they can check if there is any recurring faults due to maybe casting slippage or machine tool setup or parts supplied from outside supplliers etc.
When Ford wanted a high performance unit for the Puma they commisioned Yamaha to design it. Before they put it into production they ran it flat out to see how durable it was,After running for 2 weeks solid they gave up and pulled it apart to find it was perfect.
The trouble in getting accurate figs is . On most cars you can go to companies like Warranty Direct and get info on what they continue to breakdown with but 95% of Porsche are on their own scheme.
Also manufactures have different ways of going about fixing problems.
I know Mercedes are very good at carrying out mods when you put the car in for service without owners even knowing. We put a A class in for a A service and the warranty bill came to £2000 due to their be mods to the Trailing arms ,Brake system and new steering column all of which had give us no problems what so ever.
Some companies are more transparent than others.
Thanks again for a most informative post!
Your point about Warranty Direct provokes many thoughts, and the implications are not very encouraging.
For those still knocking the value of this thread, please note that only a very tiny proportion of unhappy customers bother to complain in writing. On that basis, negative postings here about reliability are still only a very small proportion of the reality. So if anyone still wants to, may I respectfully suggest that instead of knocking this thread, you go and ask Warranty Direct or Porsche for facts. Armed with said facts, please inform this forum. Until then, please add stats, or leave well alone. Thank you.
I still expect the failure rate to fall, but I am now confident that we're looking at double figures in percentage terms, and not single figures as I first expected six-nine months ago.
Back to Dunit: Merc took a big hit on warranty claims (and profitability), leading to significant changes for the better. Porsche do not appear to have taken a hit - maybe because so many buyers in Blighty think it is normal to write large cheques to maintain this premium product (annual warranty premiums, or big bills).
The yanks have a four year warranty and they pay less for these cars than we do in the UK! Go figure.......
Hi There all,
Ballcock did ask me to post my story here :
I owned a Boxster 2.5
covered in 9 years 360.000km which equals to 225.000 miles.
Never had any mechanical problems, except for the normal wear such as a replaced alternator, started reconditioned, fuel pump changed.
Adding gas in the aircon.
And a few tires and brakepads, but otherwise this car gntlemen never let me down and gave me hours and hours of pleasure.
Before you want to reply, no I did not drive it like a saint, but I v kept myself to my number one rule, when cold treat her nice, when hot go for it.
Now I v changed to a 996, not because the boxster was finished, no just because I could do a superb deal on this low mileage 996 Cab.
Best regards
ROnny Vandereydt
Ballcock did ask me to post my story here :
I owned a Boxster 2.5
covered in 9 years 360.000km which equals to 225.000 miles.
Never had any mechanical problems, except for the normal wear such as a replaced alternator, started reconditioned, fuel pump changed.
Adding gas in the aircon.
And a few tires and brakepads, but otherwise this car gntlemen never let me down and gave me hours and hours of pleasure.
Before you want to reply, no I did not drive it like a saint, but I v kept myself to my number one rule, when cold treat her nice, when hot go for it.
Now I v changed to a 996, not because the boxster was finished, no just because I could do a superb deal on this low mileage 996 Cab.
Best regards
ROnny Vandereydt
The incidence of RMS failures recorded is far higher than our customer base or customer records experience - I guess one car in 50 seems to have a problem during a 3 year period but not one in 5 - so I think there must be some element of posting if your car had a fault and perhaps not bothering if it hadn't.
Mind you we always recomend a new seal when doing a clutch etc - so perhaps we intercept more often. (My 0.01% (in a previous posting) was sarcastic but was relating more to very serious engine problems and of course we don't actually know the figures - but Porsche do! - I was just trying to reflect the fact that it is relatively rare).
However with so many having an RMS problem I have revisited the problem and spent longer analysing it and have come up with a new explanation that makes good sense and so we are going to experiment with a new solution and then - after a reasonable period of time - if it works we will inform others.
Baz
Mind you we always recomend a new seal when doing a clutch etc - so perhaps we intercept more often. (My 0.01% (in a previous posting) was sarcastic but was relating more to very serious engine problems and of course we don't actually know the figures - but Porsche do! - I was just trying to reflect the fact that it is relatively rare).
However with so many having an RMS problem I have revisited the problem and spent longer analysing it and have come up with a new explanation that makes good sense and so we are going to experiment with a new solution and then - after a reasonable period of time - if it works we will inform others.
Baz
hartech said:
The incidence of RMS failures recorded is far higher than our customer base or customer records experience - I guess one car in 50 seems to have a problem during a 3 year period but not one in 5 - so I think there must be some element of posting if your car had a fault and perhaps not bothering if it hadn't.
sarcasms turned on and set to fullNo really, who’d have thunk it?
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