[Saff]

Hi and thanks for the response. I can't say for sure which it would be other than the refractometer reading which I suspect bases it's findings on the specific gravity of the coolant. I assume that the higher the SG the higher the protection. I'm also quite happy to be corrected here. The service manual says the coolant is 'for life' so maybe the system has been broken into for reasons I'm not aware of. I'm tempted to have the system flushed and refilled. Food for thought anyway.