SeanR

I've not bought any that are worth a damn, if someone can recommend a good set up that would be great.

vanster

GEEZE GUYS
I didn't think this would turn into such and interesting conversation. I have a gallon of Porsche coolant and a gallon of G-05. I always thought the really big deal was not to use "green" in an aluminum engine. I use green in my Sunbeam Alpine ( iron block,aluminum head)

SeanR

Green has always been okay, you do not want to use orange.

worf928

I guess it's been a year or two since a coolant thread spawned.

Yup. The G-40 will do the same thing.

On the original topic:

For the last close-to-20 years I've been using - when not specifically requested to use something else - Prestone Long-Life coolant. This stuff is for use in aluminum engines and 'mixes with any color coolant.'

I have seen no indication that it does anything 'funny' on the inside or outside of a 928 engine as far as I can tell.

A couple of months ago, I delved into the G-40 vs. G-05 vs. Prestone thing again.

Some URLs:
https://www.penriteoil.com.au/assets...5/Coolants.pdf
https://hd.valvoline.com/our-products/zerex-g-40r
https://www.valvoline.com/our-produc...reeze-products

For coolant it's all about the additive package. Additive packages in coolants are about corrosion protection and lubrication for both metal and cooling system seals.

As far as I know Porsche's newest branded coolant is basically G-40 but it isn't crystal clear that it is better for our 928s than Zerex G-05. The G40 is Si-OAT based which means silicates are re-introduced while the G-05 (H-OAT) is very-low in silicates.

From what I find, H-OAT-based coolants are for pre-96 and Si-OAT for for post-'95. For Porsches. No idea why.

Either G40 or G05 will likely be fine - I suppose - but I worry that the lubrication/protection package of the G40 might not be what we want for the materials in our pre-'96-technology engine.

On the other hand, our cars were originally shipped with coolant that was neither silicate and phosphate free. So, adding back-in the silicates in G40 probably won't hurt as long as the coolant is regularly changed.

It's harder to figure out what's in the Prestone. Might be shyster pee. However, so far, it seems to be doing well for me and the 928s I put it in.

I will have more long-term data on the Prestone this winter, when I get a 928 in the shop that's had this coolant in it for at least 12 years (and about 2k miles) without a coolant change.

Next winter, if all goes according to plan, I'm going to pull the engine on the '91. It's had nothing but regular changes of the Prestone for 20 years.

NoVector

Oh, and don't forget G-48 which is blue... Actually says for the Porsche 928 on the jug. Zerex also sells their version of G-48.

hacker-pschorr

Talk about rubbing salt in the wound, look up, we now have blue coolant...........but blue brake fluid is illegal!!!!!!

worf928

And!!! What's interesting is: "Low silicate, low pH and phosphate free formula."

More-curious is that the US Zerex (valvoline) website 404s on a search for G-48.

This page:
https://www.valvoline.com/en-austral...ntrate-coolant

... seems to be for Australia.

I think it's probably the same as:

http://www.pentosin.net/specsheets/Pentofrost_A3.pdf

I'm somewhat convinced that Pentosin is the original manufacturer for Porsche's branded fluids.

Maybe G-48 is the new hotness.

NoVector

Dave - They sell Zerex G-48 here in central Texas at O'Reilly's. I used the Glysantin brand the 6 years I lived in Germany with no ill effects but haven't tried Zerex. I brought back 3 jugs of Glysantin so I'm GTG for a couple more years lol.

SRaouf

My 85S2 had red coolant when I bought it. It had been sitting a while (ok 15 years) and when I took the head off the gasket was rusted to buggery and there where some corrosion spots on the head surface. Luckly all but one where skimmed off. Ill be using hoat when i put it back together as thats what is recommended for my 124 merc which is also from the same era.

captainOCD

I used peak global lifetime in my car.

SeanR

We are using that in one of the local 928's to see how it fares. It's a newly rebuilt engine so I'm sure it will be good for 30 years anyway. Not the coolant, but everything else.

Chris Lockhart

I didn't research how long the G-40 has been out, so I wondered if a Rennlister had maybe run the G-40 for a year or so, and then drained and inspected what came out. Possibly see if crusty debris, weird goo, or any other abnormalities that could indicate a problem with the coolant type showed up. Then they could answer the question without making the person who asked it feel stupid.

hacker-pschorr

Sorry if you took it that way, but it was an honest question since I have no idea what to "look for" with a 40 year old car I haven't owned since new. Crusty debris, weird goo or other abnormalities could be due to a couple of reasons why, not all necessarily due to the coolant.
Maybe the new coolant is doing it's job of cleaning and knocking stuff loose? I have no idea.
There are so many variables in this scenario.
How thorough were previous coolant flushes? Ever flushed out a radiator? It can be a painstaking task to get every last bit out.

Doing a water pump on my '03 Yukon 6 years ago, I decided to do a complete flush. I poured gallons (like 15) of water through the heater core until everything came out clear, this with less than 100k miles on it.
I recall flushing the heater core in my 81 many years ago, how many people do that? It took a bit of water too before that was clear. Years later pulling the heads for a valve job the gaskets were actually fine, so where did that debris come from?

Bottom line from my point of view, that unless you start with a 100% perfectly clean and totally refreshed engine, heater core, and radiator. Pour in coolant X, and after 2 or so years see something negative, you don't really know. Yes it's frustrating but that's why we have threads like this.

So as I said earlier, bottom line is to use something rated for aluminum engines and change it every X years or so.

Evans water-less coolant it looking like a better option all the time.

Chris Lockhart

I'm sorry, maybe I read too much into it. I took it as a snarky "attack" if you will. I stand corrected.

As to the abnormalities, I have seen several GM vehicles with their stupid pink crap, that even after only a few months had strange brown good and one had a kind of clear jelly like substance. In the cases I'm familiar with the owners switched to a Prestone product (after massive clear water flushes) and after a year, no further goo. I know that many products are more hype than really being "the next big thing" and I don't want to fall into the trap of believing the hype.

As for the Evans, I have seriously thought about it, but was talked out of it, by several Rennlisters due to the issue of "away from home and get a leak, what do you put back in it?" I still think it's a legit good product, if you make sure you have good PM pract9ices to mitigate the chance of leaks, blown hoses, etc. One fellow running the Evans said he tried the regular formula and felt it was too thick for the 928's system, and switched to the 4 stroke motorcycle formula which is thinner, and has been running it with great results ever since.

hacker-pschorr

Yea, didn't mean to come off that way, it's a difficult question to ask. Same with motor oil. I see people ask: "How was your experience with X oil?" My first thought is....if the engine hasn't failed then the experience is pretty good.

Don't get me started on that GM crap and all the cars that come filled with it (not just GM unfortunately). Many claim the primary culprit of the sludging issue with that coolant was cross mixing with other coolants. That's why I spent so much time flushing my Yukon. When I pulled the pump I saw green liquid, and it was orange in the reservoir. I knowingly bought the truck with the leaking pump so the previous owner was topping off with the green stuff, not good.

That is what makes me nervous about any "new" formula. Is this really designed with the best interest of the engine or some EPA or other environmental reasons? In the late 90's oil formulations changed for the sake of the environment and we all know how that worked out.