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I don't actually read about any problems here from model year 2023 onwards.
How the radiator problem was solved... I have no idea.

Yes Clemens and you have covered considerable Kilometers in yours already

They fitted a dashpot I assume to stop thermal shock.

Yes I had that done John but unfortunately another radiator went after that. Surely somebody must know the answer, can't beleive it's still ongoing.

Sir P

I believe they identified it as thermal shock in the end.. when this all kicked off they were not thinking that way and redesigned the radiator mounting brackets and made some design changes to the radiator, then they started thinking thermal shock and fitted the swirl pots, after that more rad and mounting changes, lastly the ECU was reprogrammed to change the way the ECU controlled the engines cooling rotary valve, the engine(s) use a ECU controlled rotary valve rather than a simple thermostat to divert the flow through various parts of the engine during its warm up, this resulted in a sharp release of hot water flow to the radiator when it hit final operational temp and thus thermal shock. I had heard that BMW worked with the factory in the end to change the ECU warm up. We ended up with 3 radiator changes in our Plus Six, the last one was with a revised mounting system and the reprogram of the ECU. You can see a difference now in the warm up, it comes up to temp gradually like you are used to seeing in older vehicles, previous to this the temp gauge ran cold for quite a while, and then suddenly it would go to operating temperature, then drop back and then come up to operating temp again.
I still check the water level every day, but since the last upgrade a year ago so far so good..

Mine comes up to temp slowly.

Thanks for the answer Dave. Just shows what happens when you start using fancy engines, should have stuck with the Coventry Climax.

With my PlusFour MY2022/12, the temperature rises evenly to 100 °C. Takes approx. 5 minutes when the engine is cold, depending on the driving style

I believe that any CX that comes in for a radiator leak/change is now given the ECU reprogram, plus the ones coming through being serviced, so I would guess that most if not all now have the changes to the ECU. A nice slow warm up is a good sign...

Checked mine today 5 mins or so to hot.