I picked up a copy of Porsche Club GB's magazine while in the UK recently. An article on waterless engine coolant caught my attention, which you can read here (10MB PDF.) As frequent forum readers will be aware, on that side of the water cylinder bore scoring is the main cause for M96/97 engines to go boom, whereas over here it is the IMS devil (yes my tongue is firmly in my cheek.)

For the TL;DR; among us, cylinder scoring might be caused by localized overheating. With water-based coolant localized overheating is more likely because - well read the article to find out. Localized overheating does not occur with synthetic coolant doesn't, so it much be better.

The vendor of the product is Evans Waterless Coolants. Personally, I'm going to focus on doing a much overdue coolant flush and use the Porsche coolant that I already have on my shelf, but I figured I'd share the info and give us all Something Else To Worry About(TM)

 

It is very puzzling to me how bore scoring apparently blamed on the lack of proper cooling is a problem in a mild climate region like the UK but owners of these cars in other regions where temperatures can get much higher do not seem to have this problem with their engines.

 

They have very hard water?

 

Maybe because a colder cylinder has more expanding to to do while getting up to operating temperature than one in a car in a more moderate climate ,
I imagine the pistons heat up and expand super fast because there is combustion above them and colder cylinders cant catch up in time, hence scoring.
I don't really know what I'm talking about, but think I'm on the right track

 

Your theory is plausible.

But if this explains the bore scoring, assuming there is any real issue rather than just the one or two early failures due to some other underlying problem that gets blown up into an inherent bore scoring problem, then any special coolant is not going to help. The problem arises from when the engine is cold, not hot.

 

So I read some more about it and it seems to be commonly used in vintage cars and certain automotive-based aircraft engines (Rotax) The lack of water means no corrosion, which is beneficial in antique vehicles. However, while the waterless coolant does turn into steam at high temperatures, potentially causing cavitation, it is less efficient than water at removing heat. Therefore, the system will run hotter overall. I do not know if this matters in practice.

Related to the coolant itself, I think ambient temperature due to climate is a red herring - presumably the temperature of the coolant is high enough that ambient temperature due to climate is not a significant factor.

One theory could be that every engine in the UK is subject to the same climate, but in the US there is much more variation in climate. If there are more M96/97 engines in the US than in the UK, it stands to reason that any cold climate-related issues are going to be more prevalent in the UK.