8 cylinder front engine iconic vehicle
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By hlee96
#73324
Sorry if this opens a whole can of worms, but I am about to have Stan (@MrMerlin) help me get my '78 #414 going next week (mostly electrical stuff/fuel pump), and I want to get the correct coolant in there so I can dump my reserve of Zerex G-05 away after reading the Rennlist threads. The car received new Laso plastic impeller pump with new screw set, Gates belt, and new tensioner rollers.

So, I gathered from the 21 pages (ongoing...) that Dave (@worf928) recommends Prestone Extended Life. (https://prestone.com/products/?detail=AF2000)
1. Can I assume that the correct Prestone is the "TEAL" colored one that is specifically for "Porsche older than 1999"?

GB recommends Porsche coolant & Pentosin NF

Is this correct?

Thanks!
-Hoi
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By Erik N
#73337
What's wrong w/ G-05?
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By hlee96
#73360
I think Jim posted his experience with Zerex G-05 in this thread and subsequent pages of discussions showed that both Dave and Greg recommends against it and instead use Porsche/Pentosin NF or Prestone Extended Life (?color)
https://rennlist.com/forums/928-forum/1 ... rever.html
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By worf
#73410
This is a heavy edit of the original post.

Prestone Long Life is green. I’ve been using it for 20 years and I know from one engine tear down - in which that coolant sat for 14 years - that it works.

Otherwise, from the thread on TSTSNBN, and I’ll not argue about who recommended what:

Pentosin NF.

Or Prestone Long Life.

After much review of what I posted, the sources, and new information in the original thread on the other site, I cannot convince myself to recommend either G-40 or G-48.

Note that I also highly recommend flushing the heater core to get rid of as much G-05 (or other ‘unknown’ coolant) when switching. Pour into hose on output side of heater valve and direct the outflow from the ~1-inch overflow hose detached from the water bridge.

Furthermore, unless you know exactly what kind of coolant is in the car I would also do a distilled water flush before changing coolants.

The various flavors of "Violet"-colored coolant are not compatible with each other.
Last edited by worf on Sun Apr 18, 2021 5:37 pm, edited 3 times in total.
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By worf
#73413
hlee96 wrote: Thu Apr 15, 2021 7:25 am So, I gathered from the 21 pages (ongoing...) that Dave (@worf928) recommends Prestone Extended Life. (https://prestone.com/products/?detail=AF2000)
That’s it —^

I’ve no issue whatsoever with Pentosin NF. It’s just 3x the price of Prestone. But, the ‘14-year-sitting’ engine has data in my shop, the others do not.

Otherwise, I’ve switched to Pentosin Super DOT4 (*) for brakes and CHF 202 for PS/ATF fluid.

(*) DOT4 LV for modern Porsches with PSM. Non-LV for our ‘classics.’ (LV == low viscosity; required for these modern Porsches with their stability control trickery.)
Last edited by worf on Sun Apr 18, 2021 5:39 pm, edited 1 time in total.
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By Majestic Moose
#73740
My anecdotal evidence is the engine from my 1989 that had very minimal maintenance and was still fitted with the original water pump and timing belt. I know that it sat for over five years before my ownership. It was filled with green coolant that was clean as could be. The cylinder heads are nearly perfect. Green coolant will go back in with changes every three years.
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By worf
#73742
I read the posted-the-other-day 20-page pdf translation from the Russian website that “explains everything.”

It made my head hurt. I’ll probably have to read it two or three more times to make any sense of it.

I note that everyone in that thread seems to equate Prestone Long Life coolant with the original 60, 70, 80s coolant and they use both Prestone and ‘Green’ almost as pejoratives.
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By Charlie
#73841
That thread was 20 minutes I'll never have back. The Russian link was almost as hard to follow as the rest of the thread and probably had even less real information. Plus we all probably have some new malware now.
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By worf
#73860
Charlie wrote: Sat Apr 17, 2021 9:43 pm The Russian link was almost as hard to follow as the rest of the thread and probably had even less real information. Plus we all probably have some new malware now.
Oh I sure as Hell wasn't going to click that link. I read the PDF Rob Edwards posted.
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By Charlie
#73903
I took a few precautions so I doubt I got any eastern European virus variants. But if you're out of beautiful female GRU agents that certainly would be an effective net.

On the main topic: My heads before rehab were among the worst that ever appeared on R-list. So my coolant is Dave's coolant. It's cheap, easily available, and is the 'green' standards. Sometimes the easiest is also the best.
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By worf
#73930
Charlie wrote: Sun Apr 18, 2021 11:21 am But if you're out of beautiful female GRU agents that certainly would be an effective net.
Google is uncharacteristically unhelpful with an effective response. I’ll have to leave this Onnatop:

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By Charlie
#73944
And they're off...

928 derangement syndrome: My thoughts went immediately to the outfit - worthy of an upholstery thread.

I was thinking more old school: Tatiana Romanova, GRU agent who fakes a defection to embarrass the British Secret Service and subvert 928 threads.
Attachments
amsoil coolant bond.jpg
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By worf
#73955
Charlie wrote: Sun Apr 18, 2021 2:10 pm ... embarrass the British Secret Service and subvert 928 threads.
Yup. A remarkable ability to subvert 928 threads.

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By worf
#73981
BACK ON TOPIC:

I was worried that I'd 'mixed-up' G-40 and G-48. AND I may have. Stand by for more posts.

First a link to my post on TSTSNBN in which I pontificate at length about coolant:

https://rennlist.com/forums/928-forum/1 ... st16215552

SECOND:

G-48 is what you want to use not G-40. I've edited the first post.

Here's a picture made from https://www.glysantin.de/sites/default/ ... 1587037758

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By worf
#73993
Except...

G-48 is still low-silicate formulation.
G-40 is still a w/silicate formulation.

NF (as well as original factory fill) was a w/silicate formulation.

G-48 is recommended for our 'vintage' Porsches.
G-40 is not.

I am still of the opinion that we want a w/silicate formulation but am not willing to recommend a coolant that isn't specifically listed for our classic Porsches. Except for the Prestone Long Life.

Clear as mud. Sorry.
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By worf
#73995
I'll attempt to come back to this over the next few days and see if I can make more sense of the non-intersecting sets of information I have.
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By SwedeInSiam
#74040
Reading all this coolant threads I'm happy we don't have much choice here in Thailand since most people only pour water into the cooling system.

I'm using Castrol Radicool (the blue stuff) and it seams to work fine.

Here's how the WP impeller and housing looked like when I got the car. It had pure H2O in it.

Original Porsche WP with metal impeller.
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A bit hard to see on the picture but it had very deep pittings (several mm deep). Filled them up with epoxi and it's still good after 6 years.
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By checkmate1996
#74358
I read that "Peak Performance" products actually listed Porsche 928 as supported..
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By Sazerac
#79400
The purpose of this thread, although the title is clear, is a little loaded. For me, the coolant is only a means to an end. The problem we are trying to solve is how to keep our 928 heads from getting SCS. Jim's thread over on the "website that shall not be mentioned" is claiming that the coolant is the cause of his head corrosion. I disagree with his conclusion that the coolant is even the main cause.

Now here, we are stating that either this coolant or that coolant is good, and this implies to some of us here that that particular coolant will save our heads. However, this is not true. Take the Prestone green coolant example. I could post pictures of at last one fairly well maintained 928 that had Prestone green coolant in it whose heads had the famous "SCS" Swiss Cheese Syndrom. Others can post a picture of apparently pristine heads using this coolant. I am actually **thinking** it's possible to find heads having been used with any coolant that still look good as well as heads in any coolant that look bad. So, my conclusion is that we are not seeing the whole scope of the problem here.

Therefore, it was my contribution on the "website that need not be mentioned" to say that perhaps the headgaskets are for some reason not all the same quality and that the problem could be there: manufacturing tolerances, material variation issues, process issues, etc. This ideas was universally rejected. However, it could also be a variety of other things like head manufacturing variations, assembly techniques in relation with headgasket tolerances, etc. Some other factor or factors taken together that have not yet been recognized are destroying our heads.

I like the Swede in Siam's approach of posting use cases and pictures. However, this thread might indeed be about the theoretically best coolant. In that case, excuse my off-topic comments, and let's just focus on silicates, phosphates, etc. Just be aware that this is not going to necessarily save your heads. And, the thread becomes a lot less interesting, because I really think G05, Prestone or Pentosin NF changed regularly will work fine. We have seen pictures of pristine head using all of those coolants. That having been said I tend to prefer the latter 2 for the aforementioned theoretical reasons.
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By worf
#79467
Sazerac wrote: Tue May 11, 2021 5:41 pm ... it could also be a variety of other things like head manufacturing variations,
Large variations in porosity of head castings seems - to me - to be a major contributing factor in the onset and extent of SCS.

Partial paste from TSTMNBN:

I have pulled a few other sets of heads with good decks but the coolant history of those 928s wasn't as well known.

And I've pulled a couple of 'bad' heads that had had "my" Prestone in them for a some years but with unknown coolant change histories for a decade or two before getting Prestone.

About the only thing that I'm pretty sure of is that using Prestone Long Life and never changing it isn't BAD if the 928 just sits.

If there's any common thread - in *my* observations - about good vs. bad head decks it is that the 'bad' head decks came from 928s with a history of being "run up to temperature once a month" rather than just sitting and with no evidence of coolant changes or evidence of maybe one coolant change.

Whereas the good decks had evidence of coolant changes and/or just sitting for years with no cycling.

One other item I've learned of lately: there are vast differences in the porosity of the cast aluminum in the heads. All these 'cheap aluminum' castings(*) are somewhat porous. Some are much more porous that others and porosity is never uniform. I *suspect* that porosity variation near the deck surfaces may have a lot to do with how bad or good some of the heads are after 30-40 years. Why? Crevasse Corrosion.

(*) Talking with the Head Tech at my local Porsche dealer a week or two ago, he reminded me that when Porsche went from cast AluSil crank cases to cheap aluminum with silicon-impregnated bores (e.g. Lokasil) that some of the engine cases were so porous that they leaked engine oil *through* the case, into and out of bolt holes. That gives some idea of how porous cheaply-cast cheap aluminum can be...
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By SeanR
#79530
Pulled the head off an '82 Euro that has had green in it the entire time and the head surface was in great shape. Head gasket was in much better shape than expected. I swear, I find more head gasket/head issues with the '90+ cars. I'll keep using green in cars using green and on cars where I'm flushing the block or rebuilding I'll use the Pink/blue and rest easy. I will not use G-05 in anything.

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By checkmate1996
#79599
My guess is that if you change it in two years anyways it won’t hurt
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By Stepson
#79602
AirtekHVAC wrote: Fri Apr 23, 2021 7:21 pm Yes, I was going to use this stuff, solely because it said 928 on the front....
Ron, that's what I'm now using as well, except I'm using the 100% stuff. No need in my book to pay Peak for distilled water.
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By N_Jay
#79603
So, what is wrong with G-05?
I don't have a wet Porsche, but do have a couple of MBs and VWs, and was told that G-05 is the same formula as MB Blue, which is supposed to be good for most German cars.
My GL320 (US build) came with Something yellow (was told G-05) and my E-350 (German build) came with Blue.
I have ben using G-05 is everything German for years. (except the E because I have not run out of MB Blue yet.)
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By worf
#79607
N_Jay wrote: Wed May 12, 2021 3:42 pm So, what is wrong with G-05?
I don't have a wet Porsche, but do have a couple of MBs and VWs, and was told that G-05 is the same formula as MB Blue, which is supposed to be good for most German cars.
My GL320 (US build) came with Something yellow (was told G-05) and my E-350 (German build) came with Blue.
I have ben using G-05 is everything German for years. (except the E because I have not run out of MB Blue yet.)
See worf @ Coolant Recommendation Thread Here Instead of being "there"

it depends upon the range of years.

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