engine shaft bearing failure, help please
Discussion
Found out that the grinding noise in the engine was the intermidiate shaft bearing, that sounds odd for a 2003 c2 with 24k on the clock.
I have a full Porsche war. so covered but finding this very odd and need some feed back. The car was just, last week, serviced and had the RMS replaced. On the first drive after the service the bearning failed which I find a bit too related to the RMS work.
Could something have gone wrong durring the RMS? If fixed what else should I have them check or be concerned about, does the bearing break up and cause damage later on?
I have a full Porsche war. so covered but finding this very odd and need some feed back. The car was just, last week, serviced and had the RMS replaced. On the first drive after the service the bearning failed which I find a bit too related to the RMS work.
Could something have gone wrong durring the RMS? If fixed what else should I have them check or be concerned about, does the bearing break up and cause damage later on?
Bear in mind as well mojo , that they'll sometimes tell you they've changed the RMS , they can use the term generically, for work done fixing a leak in the area of the seal , but have actually worked on an intermediate shaft leak , which may have been the reason yours failed so soon after the service ... It might be worth clarifying this with the centre...
There are very few "weak spots" in the new generation of Boxster/996 engines. Some have been exaggerated because owners rarely write in about having NO problems and garages only see problems that they need to repair. The engines are usually extremely reliable and capable of covering very high miles - so although we call those faults that become common "weak spots" this is more of a general term we use than a ctiticism of the product.
Those Independent dealers that are capable of analysing faults and coming up with solutions have started looking at the problems quite late on because initially faulty engines were replaced by Porsche and the original damaged engines sent back to Germany for inspection – so although rumours abounded - the actual causes were slow to be picked up and verified by the Independent network.
With labour costs in the “West” escalating and “Fashion” becoming more of a sales driver than practicality – all manufacturers are moving away from repairing labour intensive mechanisms and instead moving towards whole new replacements at modest costs (often manufactured in the Far East).
For Porsche to continue to provide superb sports cars at a competitive price I guess they had to take these facts of life on board and so there has been a change towards more modern production methods and a tendency to recommend whole engine replacements as a more viable option to rebuilding.
As a result of repairing several engines, we have identified a few “weak” areas, amongst which is the intermediate shaft.
The bearing was originally a double row but we had it reported (although never saw it) that the shafts broke through being too stiff – so a single row bearing replaced it – but then a hivo chain replaced the roller chain (which puts more load on the bearing) and then some bearings failed. Also the puny 8mm stud that held it all together (and often broke) was replaced with a bigger diameter stud. During these changes the end seal was altered
Then you could only buy a “hivo chain” replacement shaft and this didn’t run with the old roller chain crankshaft – so you had to but a new crankshaft as well to get going again. By the time all this was done – you were not far off the cost of a new engine anyway – hence this being the usual solution offered.
However – manufacturers are not so concerned about what happens to quite old products and as Porsche’s age they eventually are owned by those generally less able to afford a new engine – so eventually the Independents find more cost effective solutions for them.
For example - I believe that Autofarm have developed a replacement intermediate shaft by fitting the old sprocket onto a new Hivo chain shaft and we are also developing and testing a slightly different solution to the same problem.
Other places where there appears to be weak spots are the con rods (being snapped at the joint and not ground flat – resulting in some big end failures probably through some shells being slightly out of round and having too much load in small areas while not touching the crankshaft at all in others – which we have observed as small concentrated wear spots in the shells - leading to premature wear), bores in 996’s going oval and either cracking or possibly resulting in blow-by past the pistons which overheat the lubricating face and picks up (or seizes) on the bore on the thrust face, rapid wear on the Variocam chain guides (easy to change), stuck Variocam solenoids (easy to change), RMS leaks (improved 997 seal may solve).
We (amongst others) are developing solutions including replacement liners for cracked or seized 996 engines and collecting together good used spares – so that we can offer a wide range of options from a straight forward replacement good used engine, or a local repair (just fixing the problem) to a whole engine rebuild (that also optionally reconditions or replaces other parts at the same time) – and various options in between. We have also developed an internal menu system to quickly cost out the options and provide guide-line prices – so customers can make informed choices if the worst happens.
However – failures are still very rare and most cars are reliable and covering high mileages – with minor repairs and oil leaks to fix.
When a clutch is replaced the flywheel is easy to remove and also then change the RMS and you have to do all this anyway to look at or change the intermediate shaft seal (that often leaks as well).
If the intermediate shaft seal was changed then the stud had to be tightened up again and if it was over- tightened or just disturbed it may have promoted more rapid failure. However you do not necessarily need a new engine even if the intermediate shaft has failed and if this has been suggested, then I suggest you enlist one of your local independents who are capable of offering a solution to look into it further – as we have often repaired engines that were supposed to be beyond repair at a fraction of the new cost.
Good luck.
Baz Hartech
Those Independent dealers that are capable of analysing faults and coming up with solutions have started looking at the problems quite late on because initially faulty engines were replaced by Porsche and the original damaged engines sent back to Germany for inspection – so although rumours abounded - the actual causes were slow to be picked up and verified by the Independent network.
With labour costs in the “West” escalating and “Fashion” becoming more of a sales driver than practicality – all manufacturers are moving away from repairing labour intensive mechanisms and instead moving towards whole new replacements at modest costs (often manufactured in the Far East).
For Porsche to continue to provide superb sports cars at a competitive price I guess they had to take these facts of life on board and so there has been a change towards more modern production methods and a tendency to recommend whole engine replacements as a more viable option to rebuilding.
As a result of repairing several engines, we have identified a few “weak” areas, amongst which is the intermediate shaft.
The bearing was originally a double row but we had it reported (although never saw it) that the shafts broke through being too stiff – so a single row bearing replaced it – but then a hivo chain replaced the roller chain (which puts more load on the bearing) and then some bearings failed. Also the puny 8mm stud that held it all together (and often broke) was replaced with a bigger diameter stud. During these changes the end seal was altered
Then you could only buy a “hivo chain” replacement shaft and this didn’t run with the old roller chain crankshaft – so you had to but a new crankshaft as well to get going again. By the time all this was done – you were not far off the cost of a new engine anyway – hence this being the usual solution offered.
However – manufacturers are not so concerned about what happens to quite old products and as Porsche’s age they eventually are owned by those generally less able to afford a new engine – so eventually the Independents find more cost effective solutions for them.
For example - I believe that Autofarm have developed a replacement intermediate shaft by fitting the old sprocket onto a new Hivo chain shaft and we are also developing and testing a slightly different solution to the same problem.
Other places where there appears to be weak spots are the con rods (being snapped at the joint and not ground flat – resulting in some big end failures probably through some shells being slightly out of round and having too much load in small areas while not touching the crankshaft at all in others – which we have observed as small concentrated wear spots in the shells - leading to premature wear), bores in 996’s going oval and either cracking or possibly resulting in blow-by past the pistons which overheat the lubricating face and picks up (or seizes) on the bore on the thrust face, rapid wear on the Variocam chain guides (easy to change), stuck Variocam solenoids (easy to change), RMS leaks (improved 997 seal may solve).
We (amongst others) are developing solutions including replacement liners for cracked or seized 996 engines and collecting together good used spares – so that we can offer a wide range of options from a straight forward replacement good used engine, or a local repair (just fixing the problem) to a whole engine rebuild (that also optionally reconditions or replaces other parts at the same time) – and various options in between. We have also developed an internal menu system to quickly cost out the options and provide guide-line prices – so customers can make informed choices if the worst happens.
However – failures are still very rare and most cars are reliable and covering high mileages – with minor repairs and oil leaks to fix.
When a clutch is replaced the flywheel is easy to remove and also then change the RMS and you have to do all this anyway to look at or change the intermediate shaft seal (that often leaks as well).
If the intermediate shaft seal was changed then the stud had to be tightened up again and if it was over- tightened or just disturbed it may have promoted more rapid failure. However you do not necessarily need a new engine even if the intermediate shaft has failed and if this has been suggested, then I suggest you enlist one of your local independents who are capable of offering a solution to look into it further – as we have often repaired engines that were supposed to be beyond repair at a fraction of the new cost.
Good luck.
Baz Hartech
My brother's just had the same thing, but other way around with his Boxter (again I think an 03 with about 20-odd k miles). Engine replaced due to intermediate shaft, then last weekend his RMS went (and I mean WENT, lost all the oil through it in about 150 miles).
Maybe you do only hear the bad things (and I've had to replace a seeping RMS on my 993 for the record), but Boxters and 996's just seem to go wrong seriously too often for my liking.
Maybe you do only hear the bad things (and I've had to replace a seeping RMS on my 993 for the record), but Boxters and 996's just seem to go wrong seriously too often for my liking.
hartech said:
Other places where there appears to be weak spots are the con rods (being snapped at the joint and not ground flat – resulting in some big end failures probably through some shells being slightly out of round and having too much load in small areas while not touching the crankshaft at all in others – which we have observed as small concentrated wear spots in the shells - leading to premature wear)....
Thanks for the info, it's always interesting to hear the independent slant on things. In this case the owner has the porker warranty so no need to worry about the cost and a new engine would be a good result. However, you independents working on such solutions should do well as the 996s start to drop out of warranty.
I was interested in your comment above. I recall reading about this process of breaking the con-rods at the big ends to give big end caps that are a perfect fit and obviously don't need numbering as every one is unique. It sounded like a good idea, giving surfaces that key together perfectly and would have more resistance to lateral movement than mating flat, machined surfaces. So why is it tunring out to be bad news - are they distorting the big end with the force required to break the con-rod once the maching has already been done?
Ok an update. The lovely people of Porsche Germany have decided to send me a new engine, how good of them.
My local OPC just confirmed a new engine by the end of the week and back in to the car Monday and to me soon after.
I must say it has been a shock to have this problem but the cover by Porsche war. and Porsche assist have been very good so think its been money well spent. Also, the local OPC have been very good so my only beef is with the guy who designed that bit of the engine, anyone have his email address??
Not sure how I feel about owning a Porsche right now, love the car to bits but it just blows big holes in the bulet proof German reliability which is one of the reasons I moved from a TVR to Porsche.
Is it worse than other makes, will it happen again, is there anything on the market that provides that much fun and is reliable?
I have read a lot about other people haveing problems and seen various reponses on this forum but it somehow feels different when it happens to you.
Any advince on the first few mile on the new engine?
My local OPC just confirmed a new engine by the end of the week and back in to the car Monday and to me soon after.
I must say it has been a shock to have this problem but the cover by Porsche war. and Porsche assist have been very good so think its been money well spent. Also, the local OPC have been very good so my only beef is with the guy who designed that bit of the engine, anyone have his email address??
Not sure how I feel about owning a Porsche right now, love the car to bits but it just blows big holes in the bulet proof German reliability which is one of the reasons I moved from a TVR to Porsche.
Is it worse than other makes, will it happen again, is there anything on the market that provides that much fun and is reliable?
I have read a lot about other people haveing problems and seen various reponses on this forum but it somehow feels different when it happens to you.
Any advince on the first few mile on the new engine?
Well that's good news for you and another positive testimonial for the porker warranty cover, albeit a negative demonstration of the need for 996 owners to have it. A brand new engine can't do your car's value any harm either.
Don't know about the recommended running in routine for these engines, but in any case have fun. You can always ease the pain of an initial rev limitation by planning a touring weekend and getting all the initial miles over and done with quickly while admiring the countryside.
Don't know about the recommended running in routine for these engines, but in any case have fun. You can always ease the pain of an initial rev limitation by planning a touring weekend and getting all the initial miles over and done with quickly while admiring the countryside.
Glad to see it worked out OK - the Porsche warranty seems a good idea if you can afford it.
Con-rods of course are anyway keyed together with dowels so don't have any lateral movement anyway and the ground flat hardened surfacr can take a lot of abuse without suffering - but it is for 2 reasons that I question the rods - 1 - big ends failure is not uncommon and uneven wear patches on shells have never been seen before to the same degree on other ground flat con rods from Porsche. 2 - the cracked surface is extremely uneven and often does not leave the rod evenly halved - often there is an angle at the break which would put uneven load from the bolts onto the surface and the surface is clearly so rough that it is easy to imagine that the joint is not sitting evenly load wise as the angles of all the surface roughnes actually imparts different loads on to the rod from the unidirectional bolt tension (if you resolved all the forces). The shells are made from strip so any uneven wear can only be a reflection of an uneven circular hole in the rod after assembly and I have also come across a lot of shells that have curled around the crankshaft and no longer spring back into the rod - reflecting some shock loading or dynamic loading beyond the capability of the design, the rod or the material to support the loads. I have only ever seen this before when a piston has seized or tightened and put too much load on the shell - but this is on engines with stripped because of failures for entirely different reasons - like the intermediate shaft bearing.
If Porsche do not aLways get everything right first time - then we can only analyse evidence and try and explain it - sometimes it takes time to get the right cause and trying different things eventually bottoms the problem.
The next time I see a badly or unevenly worn big end shell I will put that rod together and set it up to measure the size and ovality (if any) to see if that confirmsd or explains the cause. If not then it is back to the drawing board and I will have to find another explanation.
Regards,
Baz Hartech
Con-rods of course are anyway keyed together with dowels so don't have any lateral movement anyway and the ground flat hardened surfacr can take a lot of abuse without suffering - but it is for 2 reasons that I question the rods - 1 - big ends failure is not uncommon and uneven wear patches on shells have never been seen before to the same degree on other ground flat con rods from Porsche. 2 - the cracked surface is extremely uneven and often does not leave the rod evenly halved - often there is an angle at the break which would put uneven load from the bolts onto the surface and the surface is clearly so rough that it is easy to imagine that the joint is not sitting evenly load wise as the angles of all the surface roughnes actually imparts different loads on to the rod from the unidirectional bolt tension (if you resolved all the forces). The shells are made from strip so any uneven wear can only be a reflection of an uneven circular hole in the rod after assembly and I have also come across a lot of shells that have curled around the crankshaft and no longer spring back into the rod - reflecting some shock loading or dynamic loading beyond the capability of the design, the rod or the material to support the loads. I have only ever seen this before when a piston has seized or tightened and put too much load on the shell - but this is on engines with stripped because of failures for entirely different reasons - like the intermediate shaft bearing.
If Porsche do not aLways get everything right first time - then we can only analyse evidence and try and explain it - sometimes it takes time to get the right cause and trying different things eventually bottoms the problem.
The next time I see a badly or unevenly worn big end shell I will put that rod together and set it up to measure the size and ovality (if any) to see if that confirmsd or explains the cause. If not then it is back to the drawing board and I will have to find another explanation.
Regards,
Baz Hartech
radron said:
Really pleased that things have worked out for you!
Does anyone have any tips on 996's that are approaching the end of Porsches Warranty coverage due to age?
Mines a 98 R reg and will be over 9 in April 07
Radon , you can get 10 years warranty from Porsche PROVIDED you get the last year before the 9th birthday of the car , i.e. warranty it again March 07 , so you can have 22 months left ............ Happy days.
mojorider said:
Ok an update. The lovely people of Porsche Germany have decided to send me a new engine,
from previous engine replacements is this really new? thought even Porsche used recon engines?
what a fantastic and balanced summary from Baz - if only PCGB/OPCs could be so upfront and honest instead of denial of an problem
mojorider said:
Ok an update. The lovely people of Porsche Germany have decided to send me a new engine, how good of them.
My local OPC just confirmed a new engine by the end of the week and back in to the car Monday and to me soon after.
I must say it has been a shock to have this problem but the cover by Porsche war. and Porsche assist have been very good so think its been money well spent. Also, the local OPC have been very good so my only beef is with the guy who designed that bit of the engine, anyone have his email address??
Not sure how I feel about owning a Porsche right now, love the car to bits but it just blows big holes in the bulet proof German reliability which is one of the reasons I moved from a TVR to Porsche.
Is it worse than other makes, will it happen again, is there anything on the market that provides that much fun and is reliable?
I have read a lot about other people haveing problems and seen various reponses on this forum but it somehow feels different when it happens to you.
Any advince on the first few mile on the new engine?
Mojo, I'm sure this must have shaken your confidence in both your car and Porsche engineering, however your comments Re going from a TVR to Porsche are from what I have read and heard, somewhat wide of the mark.
TVR have a poor reputation for their warranty response, both in parts available to make repairs and in actually warranting their engines.
On both counts Porsche have proven (in your case at least) that they take their responibilities seriously.
Furthermore, your engine should (and I repeat should !) have the udated/upgraded intermediate shaft parts and RMS fitted. Hopefully you will not see a re-occurrence of this same fault.
Good news mojo...I found the warranty to be great when the engine popped at 9k on the wifes Boxster. £725.00 for the warranty sticks in my throat, but it does buy a comforting blanket of security.
IIRC, brand new engines are only fitted to cars in the manufacturers warranty period, otherwise it's a rebuilt engine.
IIRC, brand new engines are only fitted to cars in the manufacturers warranty period, otherwise it's a rebuilt engine.
good news for you mojo and to be honest they seem to honour this fault all the time with the engine.
as for TVR well I have had friends who have had all the cars both new and used and TVR are like, whatever mate and good luck
a friend's tuscan engine went after 600 miles. it still cost him like 10k
I think he threatened Ben Samuelson with everything as he works in PR so they coughed up SOME of it, not all.
I think the OPC warranty is great value and I reckon it has paid out 2.5x worth for me this year. mainly minor faults but it is the labour that is the killer!
DC
as for TVR well I have had friends who have had all the cars both new and used and TVR are like, whatever mate and good luck
a friend's tuscan engine went after 600 miles. it still cost him like 10k
I think he threatened Ben Samuelson with everything as he works in PR so they coughed up SOME of it, not all.
I think the OPC warranty is great value and I reckon it has paid out 2.5x worth for me this year. mainly minor faults but it is the labour that is the killer!
DC
Although I have previously commended the Porsche warranty for cars under 10 years old - eventually all presently younger Porsche's will be more than 10 years old - at which point warranties become rare to find that are any good.
We offer a system that covers the full cost of services and an MOT and the labour for most repairs (except radios, alarms and air-con) from £40/month + Vat (depending upon where you bought the car, the model and your annual mileage).
You need a "C" service first (to make sure the car is OK or repair serious faults first - not neccessary of course if you buy the car from us)which for a 996 presently costs £395 + Vat and covers more than any other service I have come accross including cylinder compressions, gearbox wear, road tests and a 4 wheel laser alignment check with a comprehensive engineers report at the end.
Although it doesn't cover the cost of parts - it does cover wear and tear items like brakes and clutches and of course we are in a position to offer engine repairs and replacements with used examples or reconditioned engines as an alternative to new replacement.
More details on our web site www.hartech.org
I am not touting for business as we have one down side to our business - being too busy and with quite long lead times - but I just thought such a comment was timely in the general thrust of this posting - perhaps for the future.
Baz Hartech
We offer a system that covers the full cost of services and an MOT and the labour for most repairs (except radios, alarms and air-con) from £40/month + Vat (depending upon where you bought the car, the model and your annual mileage).
You need a "C" service first (to make sure the car is OK or repair serious faults first - not neccessary of course if you buy the car from us)which for a 996 presently costs £395 + Vat and covers more than any other service I have come accross including cylinder compressions, gearbox wear, road tests and a 4 wheel laser alignment check with a comprehensive engineers report at the end.
Although it doesn't cover the cost of parts - it does cover wear and tear items like brakes and clutches and of course we are in a position to offer engine repairs and replacements with used examples or reconditioned engines as an alternative to new replacement.
More details on our web site www.hartech.org
I am not touting for business as we have one down side to our business - being too busy and with quite long lead times - but I just thought such a comment was timely in the general thrust of this posting - perhaps for the future.
Baz Hartech
Gassing Station | Porsche General | Top of Page | What's New | My Stuff