Scored cylinder - awaiting reman. from porsche
01-02-2011, 06:39 PM
#46
However, CPO also involves a thorough inspection, so if it was making that sound and they cleared it for CPO then someone seriously dropped the ball there.
01-02-2011, 07:15 PM
#47
01-02-2011, 07:31 PM
#48
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I would take whatever you have learned about engine oil and Mobil 1 from B'sTOG site with a grain of salt. I have not been there in ages, but when I looked in, there were sure a lot of "experts".
An SAE viscosity tells you nothing about the oil's quality as cbzzoom notes. However all SAE 50, or whatever viscosity grade, must fall within viscosity limits of that SAE grade. The quality, or capability of the oil is designated by the API classification, or the ILSAC GF designation, which is now GF5.
Mobil 1 0W-40 is not designed to shear or lose viscosity. There will be some VI improver material in the product, but shearing out of grade and then oxidizing back into grade over the life in service, sounds like something from one of the "experts" that I mentioned.
All oils, "synthetics" included, thin with temperature. I would not rely on my oil pressure gauge to determine if my oil is breaking down or the VI of my oil has changed. I don't know what a track session involves with respect to time, but I can assure you that Mobil 1 will not be out of grade after a few sessions. If that were true, then you would not see many NASCAR or Indy vehicles finish many races that use Mobil 1.
Used oil analysis, while a helpful indication as to engine wear, is meaningless without trend analysis, over many oil changes, and any reliance one a one time oil analysis, will almost always lead to costly and unnecessary mechanical decisions.
An SAE viscosity tells you nothing about the oil's quality as cbzzoom notes. However all SAE 50, or whatever viscosity grade, must fall within viscosity limits of that SAE grade. The quality, or capability of the oil is designated by the API classification, or the ILSAC GF designation, which is now GF5.
Mobil 1 0W-40 is not designed to shear or lose viscosity. There will be some VI improver material in the product, but shearing out of grade and then oxidizing back into grade over the life in service, sounds like something from one of the "experts" that I mentioned.
All oils, "synthetics" included, thin with temperature. I would not rely on my oil pressure gauge to determine if my oil is breaking down or the VI of my oil has changed. I don't know what a track session involves with respect to time, but I can assure you that Mobil 1 will not be out of grade after a few sessions. If that were true, then you would not see many NASCAR or Indy vehicles finish many races that use Mobil 1.
Used oil analysis, while a helpful indication as to engine wear, is meaningless without trend analysis, over many oil changes, and any reliance one a one time oil analysis, will almost always lead to costly and unnecessary mechanical decisions.
01-02-2011, 07:51 PM
#49
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I know it is a 28 pages long document, yet it is well written and well worth it...
For example, just because Porsche decided to save a few bucks on standarizing the size of the holes in the head gasket, it affected the flow of coolant to each cylinder, hence affected the the temperature in each cylinder, hence created hot spot at critical performance, and might contribute to cylinder scoring, thus might cause other issues afterward. (something like that, sorry if I interpret it incorrectly.)
Regards,
Last edited by axhoaxho; 01-02-2011 at 08:46 PM.
01-02-2011, 08:03 PM
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The trend to lower viscosity grades is driven by the CAFE more than anything else. Certainly and SAE 50 would rarely be needed except for high speed high, load conditions. Under warranty, I would use what Porsche approves, and unless you are in the cold climes, I would use an SAE 5W-40 for most applications. Start up lubrication would be sufficient in almost all but the coldest of conditions. And I would stay with Mobil 1, and not a mineral oil, or Group III oil. However, I don't think there is a Mobil 1 5W-40 with an API or ILSAC GF4 or GF5 approval rating is there??? I know there is a diesel Mobil 1 5W-40, but I don't find the gasoline version.
01-02-2011, 08:20 PM
#51
The trend to lower viscosity grades is driven by the CAFE more than anything else. Certainly and SAE 50 would rarely be needed except for high speed high, load conditions. Under warranty, I would use what Porsche approves, and unless you are in the cold climes, I would use an SAE 5W-40 for most applications. Start up lubrication would be sufficient in almost all but the coldest of conditions. And I would stay with Mobil 1, and not a mineral oil, or Group III oil. However, I don't think there is a Mobil 1 5W-40 with an API or ILSAC GF4 or GF5 approval rating is there??? I know there is a diesel Mobil 1 5W-40, but I don't find the gasoline version.
01-02-2011, 08:52 PM
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It just occurred to me why Mobil 1 5W-40 does not have a GF5 approval. ILSAC GF oils are all energy conserving, and SAE viscosity ranges for EC oils, stop at the SAE 30 level where ILSAC is concerned. What that would mean is the Mobil 1 5W-40 would probably have higher ZDP levels than the other Mobil 1 oils intended for gasoline operation. That's my guess, I have not confirmed that.
01-03-2011, 12:48 PM
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Here is a little more on the engine oil discussion from a major additive supplier....
http://www.infineum.com/Pages/GF5-9.aspx
http://www.infineum.com/Pages/GF5-9.aspx
01-03-2011, 02:18 PM
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Perhaps the more salient question to ask is, did Porsche address the cooling disparity, as documented by Hartech, in the DFI engines? Does anyone have contacts within Porsche engineering to ask such a question? Would Porsche even acknowledge the potential condition and the head gasket change that may contribute to this condition? And finally, why would Porsche, a company with infinitely greater resources, engineering expertise, and failure data base, allow this condition happen, or worse yet, continue to exist? Is the following so strong that Porsche can thumb their nose at the owners without damage to their reputation and sales?
People can make their own determination about quality, but it seems as though the following and lack of noise that people make, contributes to some fo the ease porsche has in getting around issues.
01-03-2011, 03:52 PM
#55
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pabafree95, I would like to address your question about engine oil useage based on my 40+ years in the field of lubrication and as a former Chief Engineer with Mobil Oil.
The use of a 0w-40 oil over a 5W-40, or even a 10W-40 oil, would probably have no affect on whether or not your engine scores a cylinder. This is because, at engine operating temperature, and of course the elevated temperatures Hartech discusses, the engine sees each of these oils as an SAE 40 viscosity oil, and the HTHS(High Temperture High Shear) viscosity is essentially the same and expected to provide the required lubrication and protection as specified by Porsche. The smaller number in the SAE designation is really an indication of the oil's ability to quickly reach critical areas of the engine that require lubrication in all ambient conditions, especially colder temperatures.
Since I am still looking for my first Porsche, and don't own one as yet, I don't know what Porsche requires with respect to approved viscosity grades, other than the approval, and initial fill of Mobil 1. But, if you wanted to add possible protection for the cylinders from high temp scoring as discussed by Hartech, then you would have to move to and oil with SAE 50 viscosity, such as a 5W-50 in colder climates or a 15W-50 in warmer climates. Would this mitigate the high temp scoring that Hartech discusses? Don't know, but my educated guess would be that it offer a greater degree of protection when and if the cylinder temperature disparity were to arise in an engine.
I am not advocating using an engine oil with a viscosity designation other than what Porsche recommends. But after reading the Hartech reasearch and how and why this condition has arisen, my confidence in Porsche's engineering capabilities has been shaken somewhat. However, my search for the right car continues, but I will be cognizant of this potential condition now, just as I am about the sooting and high oil consumption. In fact, my experience tells me that the cylinder scoring may very well be related to the high oil consumption that some have discussed here, although that is speculation on my part, with nothing other than my 40+ years experience to go on.
I hope this helps.
The use of a 0w-40 oil over a 5W-40, or even a 10W-40 oil, would probably have no affect on whether or not your engine scores a cylinder. This is because, at engine operating temperature, and of course the elevated temperatures Hartech discusses, the engine sees each of these oils as an SAE 40 viscosity oil, and the HTHS(High Temperture High Shear) viscosity is essentially the same and expected to provide the required lubrication and protection as specified by Porsche. The smaller number in the SAE designation is really an indication of the oil's ability to quickly reach critical areas of the engine that require lubrication in all ambient conditions, especially colder temperatures.
Since I am still looking for my first Porsche, and don't own one as yet, I don't know what Porsche requires with respect to approved viscosity grades, other than the approval, and initial fill of Mobil 1. But, if you wanted to add possible protection for the cylinders from high temp scoring as discussed by Hartech, then you would have to move to and oil with SAE 50 viscosity, such as a 5W-50 in colder climates or a 15W-50 in warmer climates. Would this mitigate the high temp scoring that Hartech discusses? Don't know, but my educated guess would be that it offer a greater degree of protection when and if the cylinder temperature disparity were to arise in an engine.
I am not advocating using an engine oil with a viscosity designation other than what Porsche recommends. But after reading the Hartech reasearch and how and why this condition has arisen, my confidence in Porsche's engineering capabilities has been shaken somewhat. However, my search for the right car continues, but I will be cognizant of this potential condition now, just as I am about the sooting and high oil consumption. In fact, my experience tells me that the cylinder scoring may very well be related to the high oil consumption that some have discussed here, although that is speculation on my part, with nothing other than my 40+ years experience to go on.
I hope this helps.
one should check exhaust pipe from time to time when starting car from cold - if it starts to blow smoke from one side only - one connected to second cylinder bank - that is quite a typical signal of distress and in my opinion it is better to sell this car away asap.
here is where to get new thermostat:
https://www.lnengineering.com/lowtem...hermostat.html
01-03-2011, 07:24 PM
#56
BTW Lubrecon, what do you think of the HTHS rating?
You seem very knowledgeable, but what you're saying seems to go against what I've heard as "accepted wisdom" (but we all know how accurate that can be!).
In particular I've seen several posts from people who believe that Mobil 1 0w-40 has sheared at the track. They generally get this conclusion from two data points : UOA after the track weekend which shows the effective viscosity has dropped to that of a 30w , or by seeing the oil pressure drop (at the same temperature and conditions, eg. 185 F at idle) after a hard track session, from 2 bars when the oil was fresh to 1.5 bars after the track weekend (for example).
I found this info on HTHS which seems to confirm the superstition that 15w-50 oils are "strong" while the Mobil 1 0w-40 is particularly prone to shear :
HTHS - High temperature High shear A relatively new oil test/specification, the oil is subjected to high temperature 150C and is mechanically sheared at 1 x 10^6 per second. A value of 2.8 or is considered the minumum for normal bearing wear. Here are some HTHS numbers on well known oils, the higher the number the more shear stable the oil; 4's and 5's are excellent numbers and demonstrate basestock quality e.g. Silkolene and Motul.
Mobil 1 0W40 HTHS 3.6
Castrol RS 10w-60 HTHS 3.7
Castrol RS 0w-40 HTHS 3.7
Silkolene PRO S 5w-40 HTHS 4.07
Motul 300V 10w-40 HTHS 4.19
Motul 300V 5w-40 HTHS 4.51
Redline 5w40 HTHS 4.6
Redline 10W40 HTHS 4.7
Mobil 1 15w-50 HTHS 5.11
Silkolene PRO S 10w-50 HTHS 5.11
Silkolene PRO R 15w-50 HTHS 5.23
Motul 300V 15w-50 HTHS 5.33
Redline 15W50 HTHS 5.8
You seem very knowledgeable, but what you're saying seems to go against what I've heard as "accepted wisdom" (but we all know how accurate that can be!).
In particular I've seen several posts from people who believe that Mobil 1 0w-40 has sheared at the track. They generally get this conclusion from two data points : UOA after the track weekend which shows the effective viscosity has dropped to that of a 30w , or by seeing the oil pressure drop (at the same temperature and conditions, eg. 185 F at idle) after a hard track session, from 2 bars when the oil was fresh to 1.5 bars after the track weekend (for example).
I found this info on HTHS which seems to confirm the superstition that 15w-50 oils are "strong" while the Mobil 1 0w-40 is particularly prone to shear :
HTHS - High temperature High shear A relatively new oil test/specification, the oil is subjected to high temperature 150C and is mechanically sheared at 1 x 10^6 per second. A value of 2.8 or is considered the minumum for normal bearing wear. Here are some HTHS numbers on well known oils, the higher the number the more shear stable the oil; 4's and 5's are excellent numbers and demonstrate basestock quality e.g. Silkolene and Motul.
Mobil 1 0W40 HTHS 3.6
Castrol RS 10w-60 HTHS 3.7
Castrol RS 0w-40 HTHS 3.7
Silkolene PRO S 5w-40 HTHS 4.07
Motul 300V 10w-40 HTHS 4.19
Motul 300V 5w-40 HTHS 4.51
Redline 5w40 HTHS 4.6
Redline 10W40 HTHS 4.7
Mobil 1 15w-50 HTHS 5.11
Silkolene PRO S 10w-50 HTHS 5.11
Silkolene PRO R 15w-50 HTHS 5.23
Motul 300V 15w-50 HTHS 5.33
Redline 15W50 HTHS 5.8
01-03-2011, 09:34 PM
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HTHS came about in an effort to determine the minimum viscosity required to adequately lubricate and protect bearings and cylinders in real world conditions. Since it is impossible to actually measure the viscosity in these areas in an operating engine, calculations were made based on loads and temperatures that were thought to provide that protection by different oils with different SAE viscosity grades, straight and cross graded. Minimum viscosity levels were established, and reported in cP(centipoise). Anything above the minimums would theoretically provide better wear protection under all operating conditions. But of course this begs the question how much better than the minimum???
Since J300 calls out the minimums, you would have to do several Sequence tests on each oil and see how those results stack up against the HTHS viscosity of the oil in question. There is no minimum for any SAE viscosity other than a 30 or 40. But, as you have illustrated, usually the higher the SAE viscosity, the higher the HTHS vis of that oil is, and I would expect that to be the case, unless the base stock or additive package was total crap.
HTHS is really not a measure of the shear stability of the oil, just the viscosity of the oil under the test conditions, it is a lab test, not a Sequence test, done by an instrument, not in an engine.
As far as Mobil 1 0W-40 shearing out of grade under racing conditions, I guess that could happen, but let's say it did, and an oil analysis showed the viscosity to be that of a SAE 30.....unless you ran the HTHS viscosity, you would not know if it had been affected simply due to the oil shearing out of grade or had still met the minimum HTHS J300 requirement for an SAE 30.
I really would not worry about the HTHS numbers of any oil, if you are racing, use a good 5, or 15W-50 and put the pedal to the metal!!
Since J300 calls out the minimums, you would have to do several Sequence tests on each oil and see how those results stack up against the HTHS viscosity of the oil in question. There is no minimum for any SAE viscosity other than a 30 or 40. But, as you have illustrated, usually the higher the SAE viscosity, the higher the HTHS vis of that oil is, and I would expect that to be the case, unless the base stock or additive package was total crap.
HTHS is really not a measure of the shear stability of the oil, just the viscosity of the oil under the test conditions, it is a lab test, not a Sequence test, done by an instrument, not in an engine.
As far as Mobil 1 0W-40 shearing out of grade under racing conditions, I guess that could happen, but let's say it did, and an oil analysis showed the viscosity to be that of a SAE 30.....unless you ran the HTHS viscosity, you would not know if it had been affected simply due to the oil shearing out of grade or had still met the minimum HTHS J300 requirement for an SAE 30.
I really would not worry about the HTHS numbers of any oil, if you are racing, use a good 5, or 15W-50 and put the pedal to the metal!!
01-04-2011, 09:12 AM
#58
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hey pabafree95 - did you mention anywhere what the mileage was on the engine when you first noticed the noise? this is a great and very informative post. the video was also quite helpful - thx
> semi-concerned owner of an 08, 997
> semi-concerned owner of an 08, 997
01-04-2011, 11:09 AM
#59
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28,000 miles.
My frustration is that I noted this ticking noise prior to purchase.
Was reassured by the sales asso. and the GM (who has been released since)
that this noise is 'just the sound of the S engine'
I am a rookie - but learned a lot about the car in a short period of time, so in the end will be OK.
My frustration is that I noted this ticking noise prior to purchase.
Was reassured by the sales asso. and the GM (who has been released since)
that this noise is 'just the sound of the S engine'
I am a rookie - but learned a lot about the car in a short period of time, so in the end will be OK.
01-04-2011, 01:14 PM
#60
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Can you elaborate on this please, why bank 2, and why is this potentially terminal failure?