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I'm looking for an abridged version of these recommendations. Are the following statements approximately correct?
Hands down, the number one best choice, is Porsche sourced coolant. Not sure the exact name, but it is expensive relative to other options and has to be sourced via Porsche.
Pentofrost NF is a decent second choice. It's widely available and reasonably priced. It's produced by Pentosin, a German company. Be sure to use Pentofrost NF and NOT Pentofrost SF.
Even though G-05 has historically been recommended around here, nowadays it is no longer recommended.
All the "G" terminology is somewhat confusing. G-05 is bad, G-40 and G-48 are good, G-48 is really G-11, G-40 is really G-13, then there are G-12 G-12+, G-12++, G-65 is really G-12, G-64, and G-Wizz.
I'm going to switch from G-05 to Pentoforst which is G-11 aka G-48.
I'm looking for an abridged version of these recommendations. Are the following statements approximately correct?
Hands down, the number one best choice, is Porsche sourced coolant. Not sure the exact name, but it is expensive relative to other options and has to be sourced via Porsche.
Pentofrost NF is a decent second choice. It's widely available and reasonably priced. It's produced by Pentosin, a German company. Be sure to use Pentofrost NF and NOT Pentofrost SF.
Even though G-05 has historically been recommended around here, nowadays it is no longer recommended.
All the "G" terminology is somewhat confusing. G-05 is bad, G-40 and G-48 are good, G-48 is really G-11, G-40 is really G-13, then there are G-12 G-12+, G-12++, G-65 is really G-12, G-64, and G-Wizz.
I'm going to switch from G-05 to Pentoforst which is G-11 aka G-48.
Clear as mud.
I recently switched to this Peak anti-freeze. 928s are specifically mentioned on the label.
Hopefully the fact that they specifically call out 928, 968 etc. is that they did some level of testing as opposed to a simple marketing ploy. Hopefully its a good alternative to Porsche brand as I can source this locally at Advanced Auto Parts.
I'm looking for an abridged version of these recommendations. Are the following statements approximately correct?
Hands down, the number one best choice, is Porsche sourced coolant. Not sure the exact name, but it is expensive relative to other options and has to be sourced via Porsche.
Pentofrost NF is a decent second choice. It's widely available and reasonably priced. It's produced by Pentosin, a German company. Be sure to use Pentofrost NF and NOT Pentofrost SF.
Even though G-05 has historically been recommended around here, nowadays it is no longer recommended.
All the "G" terminology is somewhat confusing. G-05 is bad, G-40 and G-48 are good, G-48 is really G-11, G-40 is really G-13, then there are G-12 G-12+, G-12++, G-65 is really G-12, G-64, and G-Wizz.
I'm going to switch from G-05 to Pentoforst which is G-11 aka G-48.
Clear as mud.
The Porsche coolant recomended these days is G-48. The "G' is derived from the company that developed the formulation- Glysantin who just happen to be owned by BASF the biggest chemical conglomerate in Germany and quite understandably the Germans tend to stick together when they have superior products as is often the case. Thus it is a fair bet that they make the coolant you see in a jug with Porsche written on it with appropriate mark up.
G-48 is a hybrid OAT or "HOAT" coolant. So is G-05 that was the original HOAT coolant that hit the markets around 1994. From a chemical perspective they are basically the same class of coolant but the G-05 has an additional element in that it also has some capability that somehow helps protect against corrosion in wet liner engines. Our engines do not have wet liners so in terms of chemistry and what they do they are one and the same thing and both should be perfectly OK in our motors not that all of our friends agree with that premise as discussed in this thread.
The fact that non of these coolants was around when our 928's were made seems to escape the attention of many and the IAT type coolants of the day that were originally used [usually green coloured] are still perfectly acceptable. They only went out of favour for environmental considerations because they have a more limited life span. The "new technology" OAT coolants were designed to stop this but they generally failed quite miserably so they created the HOAT coolant which took a step backwards by re-introducing silicates back into the brew and as I can tell they form the base protection of both the IAT and HOAT coolants.
The fundamental problem is that ethylene glycol, although an excellent antifreeze, has the unfortunate habit of breaking down to form highly corrosive organic acids when it exceeds temps of 50C as in our cooling system. Silicates are and remain the same prime ingrediant to stop this. As long as the coolant pH remains alkaline it is an indication that the silicate package is not exhausted. I have just changed my coolant after 4 years- it still registered pH approx 8.5- not too surprising as I do not do much mileage but supports the notion about life expectancy.
The IAT coolants also contained phosphates to protect the cast iron heads and blocks tpyically found in older US heavy metal. The problem with phosphates was that mix them with anything less than distilled water purity and they form scale deposits on the cooling surfaces. Modern coolants are much less sensitive to such.
The really hilarious bit is the notion that IAT coolants only last two years. In reality their life expectancy is based on run hours and the manufacturers seemingly reasoned that coolant life was based on average mileage but that was just not the case. Of course assume that the average mileage is 15k miles per year so over two years is 30k miles. Assume an average speed of say 50 mph and then you can work out the likely life span in run hours and even that will probably be conservative. Of course if one changes the coolant every two years then they sell more coolant- what a surprise!
Today, during my Porsche support activities (aka employment), I reviewed a list of some 250K part transactions.
My task was to identify and classify coolant based on a hodge-podge list of descriptions to perform a cost analysis. The company I work for has purchased/sold roughly $100,000 worth of coolant already this year.
I'm trying to develop a simple way to classify coolants. Between this thread and other research, it's not necessarily an easy task.
I think we have 7 or 800 hundred techs and evidently, there isn't a simple standard classification.
Since there are people far more knowledgeable than me on this topic, I would love to pick your brains.
If you were asked to categorize coolants into broad classifications for pricing purposes, what would you use?
Know of multiple cars running G05 since early 2000s with no corrosion issues or head gasket failures. G05 was the primary choice of antifreeze for Mercedes since it's intro, and those are all aluminum engines too. No known failures internally outside of failure to maintain and service at proper intervals (4 or 5 years).
You have a higher chance of Dexcool and the original green antifreeze killing your engine....Dexcool probably higher on that list by a lot.
Hell even original green antifreeze ain't bad as long as you change it every 2 years religiously.
If you were asked to categorize coolants into broad classifications for pricing purposes, what would you use?
Got to love a taxonomy/market segmentation question I'd go with application-related segmentation/classification by purpose (you didn't specify the application so I won't assume vehicles at this stage), then benefit-aligned sub-segments
And then maybe segment by:
concentrate vs pre-mix (cost efficiency vs ease of use)
long-life vs regular (I suspect people will pay more for perceived protection benefit of long-life, but then still change regularly).
You should be able to use the various manufacturer standards as reference lookup to do much of the top level, and descriptions to do the second? (yay data analytics)
The Porsche coolant recomended these days is G-48. The "G' is derived from the company that developed the formulation- Glysantin who just happen to be owned by BASF the biggest chemical conglomerate in Germany and quite understandably the Germans tend to stick together when they have superior products as is often the case. Thus it is a fair bet that they make the coolant you see in a jug with Porsche written on it with appropriate mark up.
G-48 is a hybrid OAT or "HOAT" coolant. So is G-05 that was the original HOAT coolant that hit the markets around 1994. From a chemical perspective they are basically the same class of coolant but the G-05 has an additional element in that it also has some capability that somehow helps protect against corrosion in wet liner engines. Our engines do not have wet liners so in terms of chemistry and what they do they are one and the same thing and both should be perfectly OK in our motors not that all of our friends agree with that premise as discussed in this thread.
The fact that non of these coolants was around when our 928's were made seems to escape the attention of many and the IAT type coolants of the day that were originally used [usually green coloured] are still perfectly acceptable. They only went out of favour for environmental considerations because they have a more limited life span. The "new technology" OAT coolants were designed to stop this but they generally failed quite miserably so they created the HOAT coolant which took a step backwards by re-introducing silicates back into the brew and as I can tell they form the base protection of both the IAT and HOAT coolants.
The fundamental problem is that ethylene glycol, although an excellent antifreeze, has the unfortunate habit of breaking down to form highly corrosive organic acids when it exceeds temps of 50C as in our cooling system. Silicates are and remain the same prime ingrediant to stop this. As long as the coolant pH remains alkaline it is an indication that the silicate package is not exhausted. I have just changed my coolant after 4 years- it still registered pH approx 8.5- not too surprising as I do not do much mileage but supports the notion about life expectancy.
The IAT coolants also contained phosphates to protect the cast iron heads and blocks tpyically found in older US heavy metal. The problem with phosphates was that mix them with anything less than distilled water purity and they form scale deposits on the cooling surfaces. Modern coolants are much less sensitive to such.
The really hilarious bit is the notion that IAT coolants only last two years. In reality their life expectancy is based on run hours and the manufacturers seemingly reasoned that coolant life was based on average mileage but that was just not the case. Of course assume that the average mileage is 15k miles per year so over two years is 30k miles. Assume an average speed of say 50 mph and then you can work out the likely life span in run hours and even that will probably be conservative. Of course if one changes the coolant every two years then they sell more coolant- what a surprise!
They have quite different ideas than you are putting forth and offer 3 distinct different coolants for Porsche models.
I'd be interested in your insight as to why they are suggesting what they do.
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
I recently switched to this Peak anti-freeze. 928s are specifically mentioned on the label.
Hopefully the fact that they specifically call out 928, 968 etc. is that they did some level of testing as opposed to a simple marketing ploy. Hopefully its a good alternative to Porsche brand as I can source this locally at Advanced Auto Parts.
You might be on to an economical alternative, sir!
Very interesting that Peak is drawing a distinct line, in the sand, between the early water cooled Porsche models (924, 944, 928, and 968) and the later model water cooled Porsche models (everything made from 1998 on), by distinctly calling those early models out, with this offering.
I wonder is this is just a coincidence or they know more than we know, as Pentosin makes the same distinction, with what they offer. (http://www.pentosin.net/f_antifreeze.asp.)
It would be fun to figure out if this offering from Peak is G11 based, like the Pentofrost offering.
They have quite different ideas than you are putting forth and offer 3 distinct different coolants for Porsche models.
I'd be interested in your insight as to why they are suggesting what they do.
Greg,
Have visited their website together with a good number of other coolant manufacturers when I was trying to fathom out what the heck was going on and it all started some 15 years ago when Porsche wanted to put some 16 litres of their coolant in my 928 and advised the cost for such "privilige". I did some homework and told them to stick the Prestone traditional green coolant in my 928 which they duly did. I cannot remember the mark up but it was something like 5 times the cost.
With regard to your post perhaps you would be kind enough to advise what you have spotted that contradicts anything written on the Pentosin website as I cannot spot anything. All I can see at first glance are two coolants that cover the Porsche range- the G11 [blue] for the likes of our 928 and other models of the day and then the G12 [pinkish?] for later models like my Cayenne Turbo S. One could use the G11 in the Cayenne but the G12 cannot be used in the 928 primarily because [as best I could make out] the later models avoid the use of steel.
What perhaps may not be quite so obvious was the cryptic reference i made to the code letter "G". G11 and G12 officially speaking are VW coolant codes but I reckon it is more than coincidence that the letter G is used. VW in all probability will know squat about coolant chemistry and I reckon that they used the "G" reference because they get their coolant technology from Glysantin [read BASF]. Either way G11, G48 and Porsche coolant are one and the same thing. Glysantin advise on their website that VW G11 and their G48 are one and the same thing- of course they say nothing about who makes coolant for Porsche but it seems pretty obvious to me who does! Valvoline even used to make a G11 and a G48 coolant.
Now cast your mind back to when you were a young tearaway- do you remember ever seeing any coolant that was not green? Until about 1994 IAT coolant was the only coolant available and it was designed to protect engines with aluminium and iron content [US motor companies probably dictated the content of coolant, As I could fathom these coolants had phosphates in them primarily to stop corrosion in the iron blocks and heads. Gradually aluminium alloys took over so the need for phosphate based coolants seemingly declined rapidly led of course by German manufacturers. Ze Germans did not like phosphates because when mixed with hard water scale is formed and as I understand most of the water in Germany tends to be rather hard. The industry tried to migrate to OAT technology but failed. The catch all answer was meant to be G-05 coolant and from 1994 it took hold in Europe but ont in the US where IAT still ruled the roost. Slowly but surely things changed and then the industry then ended up with this variant and that variant and a hell of a lot of confusion that still reigns to this day.
So, if like me one still uses IAT technology, old as it is it works just fine and dandy but on paper it does not have the service life of modern specs but as I cooncluded earlier, in reality it lasts longer than most folks think it does.
Anyway, if you see anything not aligned with the Pentosin [or any other manufacturer] kindly point such out and i will gladly give you my take on it. Not difficult to see why folks like Kurt get confused!
Have visited their website together with a good number of other coolant manufacturers when I was trying to fathom out what the heck was going on and it all started some 15 years ago when Porsche wanted to put some 16 litres of their coolant in my 928 and advised the cost for such "privilige". I did some homework and told them to stick the Prestone traditional green coolant in my 928 which they duly did. I cannot remember the mark up but it was something like 5 times the cost.
With regard to your post perhaps you would be kind enough to advise what you have spotted that contradicts anything written on the Pentosin website as I cannot spot anything. All I can see at first glance are two coolants that cover the Porsche range- the G11 [blue] for the likes of our 928 and other models of the day and then the G12 [pinkish?] for later models like my Cayenne Turbo S. One could use the G11 in the Cayenne but the G12 cannot be used in the 928 primarily because [as best I could make out] the later models avoid the use of steel.
What perhaps may not be quite so obvious was the cryptic reference i made to the code letter "G". G11 and G12 officially speaking are VW coolant codes but I reckon it is more than coincidence that the letter G is used. VW in all probability will know squat about coolant chemistry and I reckon that they used the "G" reference because they get their coolant technology from Glysantin [read BASF]. Either way G11, G48 and Porsche coolant are one and the same thing. Glysantin advise on their website that VW G11 and their G48 are one and the same thing- of course they say nothing about who makes coolant for Porsche but it seems pretty obvious to me who does! Valvoline even used to make a G11 and a G48 coolant.
Now cast your mind back to when you were a young tearaway- do you remember ever seeing any coolant that was not green? Until about 1994 IAT coolant was the only coolant available and it was designed to protect engines with aluminium and iron content [US motor companies probably dictated the content of coolant, As I could fathom these coolants had phosphates in them primarily to stop corrosion in the iron blocks and heads. Gradually aluminium alloys took over so the need for phosphate based coolants seemingly declined rapidly led of course by German manufacturers. Ze Germans did not like phosphates because when mixed with hard water scale is formed and as I understand most of the water in Germany tends to be rather hard. The industry tried to migrate to OAT technology but failed. The catch all answer was meant to be G-05 coolant and from 1994 it took hold in Europe but ont in the US where IAT still ruled the roost. Slowly but surely things changed and then the industry then ended up with this variant and that variant and a hell of a lot of confusion that still reigns to this day.
So, if like me one still uses IAT technology, old as it is it works just fine and dandy but on paper it does not have the service life of modern specs but as I cooncluded earlier, in reality it lasts longer than most folks think it does.
Anyway, if you see anything not aligned with the Pentosin [or any other manufacturer] kindly point such out and i will gladly give you my take on it. Not difficult to see why folks like Kurt get confused!
Kurt's confused.
I'm confused....and concerned if what I'm doing is correct.
It seems very strange that Pentosin would offer 3 specific coolants for the different Porsche models, while Porsche would offer only one.
Some sort of magical Porsche "pink", $50 a gallon coolant which has special additives that allow it to work on all of their cars?
Or are they simply not concerned with the '76-'95 cars and saying that the current "pink" coolant is good enough?
For years and years, I used a "ZVW 101 ??? blue coolant in all of the 924's, 944's, and 928's, and 968's Then Porsche brought out their own coolant (which was blue) and told me that the "ZVW" coolant was NLA.
Several years back, Porsche changed their coolant to the current pink color and the blue coolant was discontinued.
Quite interesting that the colors that Pentosin offers are the same as what I used to use and the same as the pink Porsche coolant that I currently use. Yet, they claim these colors are for different Porsche applications.
In the end, there's simply too many choices and not enough solid "you must use this, because of this" statements from Porsche. Additionally, as the years pass, I'm taking apart more and more 928 engines with worse and worse aluminum "pitting"....yet the coolants were radically "improved" 20 + years ago.
One of the engines I'm currently doing is a '94 GTS engine that was so bad that I had to weld up pits on the outer edges of the block where the head gasket sits! The heads were absolutely awful and required a lot of repair.
If the rate of deterioration continues, in another 20 years, 928's will only be museum pieces...not able to actually run, because they won't hold water. (Which may be a moot point, if there is no longer any gasoline.)
Kurt's confused.
I'm confused....and concerned if what I'm doing is correct.
It seems very strange that Pentosin would offer 3 specific coolants for the different Porsche models, while Porsche would offer only one.
Some sort of magical Porsche "pink", $50 a gallon coolant which has special additives that allow it to work on all of their cars?
Or are they simply not concerned with the '76-'95 cars and saying that the current "pink" coolant is good enough?
For years and years, I used a "ZVW 101 ??? blue coolant in all of the 924's, 944's, and 928's, and 968's Then Porsche brought out their own coolant (which was blue) and told me that the "ZVW" coolant was NLA.
Several years back, Porsche changed their coolant to the current pink color and the blue coolant was discontinued.
Quite interesting that the colors that Pentosin offers are the same as what I used to use and the same as the pink Porsche coolant that I currently use. Yet, they claim these colors are for different Porsche applications.
In the end, there's simply too many choices and not enough solid "you must use this, because of this" statements from Porsche. Additionally, as the years pass, I'm taking apart more and more 928 engines with worse and worse aluminum "pitting"....yet the coolants were radically "improved" 20 + years ago.
One of the engines I'm currently doing is a '94 GTS engine that was so bad that I had to weld up pits on the outer edges of the block where the head gasket sits! The heads were absolutely awful and required a lot of repair.
If the rate of deterioration continues, in another 20 years, 928's will only be museum pieces...not able to actually run, because they won't hold water. (Which may be a moot point, if there is no longer any gasoline.)
Pink? Blue? Yellow" Green?
Doesn't matter?
Then why bother making them all?
I think it would be much easier to count the number of folks who really understand what is going on with coolants- you might even be able to count them on your fingers! The rest of us have to muddle through the available info and put two and two together. Non of these modern coolants were available until about the time Porsche scrapped production of our gems. At that time the only new tech coolant available as I could figure out was G-05 [yellow?] that was launched around 1994. The colour dye being added as a visual cue for folks like yourself and to avoid inadvertent mixing.
When it comes to the added value of Porsche branded coolant I tend to be somewhat dismissive as just about anything that comes in a Porsche box appears to have a minimum of 100% added for the box and that on items that are not exactly cheap to start with so we should be thankful for the efforts folks like Roger, Mark A and yourself make! So when it comes to coolant what is the optimal solution? When I acquired my first 928 [the 90S4] the motor [as currently installed in my GTS] was running on Prestone IAT [green] coolant and had been more or less since new. I assumed that a continuity thing given that the Porsche coolant of that period logically should have been green colour. After losing the S4 some 16 years ago prior to instaling we opened up the motor [a couple of bent valves] and I carefully inspected the inside surfaces for any signs of corrosion, particularly the heads and the top of the cylinders. The logic was driven from having seen the heads that I got from the original GTS motor that were condemned as unrepairable by the local agents. That was just not correct but was a reflection of what Porsche tolerate [not much!]. At the same time there were two other 928's in dock with corroded heads and the local agents were baffled by this. It was at this time that I recognised the crevice corrosion attack for what it was. Never really came aross the issue again until Jim posted this thread and sure enough exactly the same characteristic damage associated with such.
When we pulled my motor there were no signs of head damage but there was a small patch of corrosion on the inner side of the outer wall about the size of a dime that made no technical sense whatsoever other than perhaps some material irrregularity. Now, if the engine is reacting to ransid coolant there will be corrosion everywhere- have you ever seen this happen? First thing I do after a coolant drain is to pull the thermostat housing and the thermostat and have a good look around for any signs of corrosion within the cooling jacket- to date have seen non whatsoever. The outside of the thermostat housing and the Y- piece are prone to corrosion- again this is a classic crevice corrosion attack. Easy to explain on these items as coolant can get trapped between the hose and the nozzle and then the attack mechaism commences once the coolant additive package is exhausted. Putting the clamp close to the raised lip will help stop this from happening and it has nothing to do with the coolant type/make. The head/gasket issue is another matter - I do not know for sure what triggers it but my favoured theory is that it is likely caused by cars that sit for months on end not being used. That is what happened to the three problemmatic examples that I examined- the owners used to go to Europe during the hot season because they could afford to. What do many enthusiast owners do in the States during winter time?- they hibernate their cars until spring. When this happens the coolant type is irrelevant. Whether or not you have come any closer to my way of thinking in that regard remains to be seen.
Whatever one's favourite brew, the important thing is to ensure the coolant remains alkali as that is what stops the thermal degradation at 50C. For examples that are hibernated I reckon that they should be run at least once a month so as to get up to temperature and complete a warm up / cool down cycle. I have a feeling that this may just permit some relaxation wherein the unsupported areas between the head gasket and the head might get replenished. This type of attack seems to take quite a long time before it ever gets noticed and by then the damage is severe. Jim's engine was in the early stages of this process and his intervention was fortuitous. I am pretty sure that engines such as mine that get run year round are much less vulnerable to such issues even if they only cover low mileages. Whether my thinking is correct remains to be seen but as I am concerned it is the only credible theory that explains in detail what is commonly happening.
The more modern engines possibly have less issues with coolant due to material advances therefore a different spec but i have not really looked into this in any detail. I run the original type of coolant [IAT] because I am confident it works. I am equally confident that the G05 works and doubtless the G11 [read G48] brew also work well. Using the stuff out of a Porsche bottle will also work well but no better than the generic brews made by credible companies like Pentosin, Valvoline, Glysantin, Prestone etc etc.
You have the luxury of being able to get whatever you want, i have to settle for whatever I can find that seems credible! Last time I checked the local agents did not have any of the Porsche coolant recommended for earlier cars- no demand as it were. They can order it from Germany but then such orders also have to pay for air freight on top of whatever it is they ask. I am about to put new coolant in the car and this time I could not even find the Prestone I usually pour in.
Re-reading this thread I'm still on the side of the fence that the water used is just as important, if not more important than the coolant.
My unfiltered well water is heavy in iron, so much so it's red out of the garden hose if I don't have the filters on. On the other side of town the city water has so many metals in it most people don't drink it. I can only imagine what this would do to a 928 engine.
I keep minimum 10 gallons of distilled water on hand at home at all times I use it so much. It's to the point I'm researching a home distilling machine to make my own.
Thanks to this thread, I'm only buying 50/50 pre-mixed coolant from now on. Sure it's more expensive, but I'm sure the coolant company is using the best water possible for their mix.
04-14-2021, 02:12 PM
I'd go with application-related segmentation/classification by purpose (you didn't specify the application so I won't assume vehicles at this stage), then benefit-aligned sub-segments
