So the point of 2bar is to keep the coolant liquid.

Although coolant certainly has a higher boiling point than water, for water these are the numbers:

At 2 bar, water boils at 120C (248F), just about the max operating temp of X5

At 1.4 bar, water boils at 109.44c (229F)

So the issue is: if the car gets to 110C, it will vent with 1.4 cap. That could be a good thing by giving you the obvious sign that it's running hot but 110 is barely over temp.

I still won't deny the logic of keeping all those mentioned 20 yr old parts at a substantially lower pressure, and the only time I've seen an x5 > 110c was when the ET split wide open and dumped the coolant.


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2011 E70 • N55 (me)
2012 E70 • N63 (wife)