I've got a tool to pressurise the coolant system via the expansion tank so I can check for leaks. The TD5 caps (Defender/D2) both vent at 1.4 bar. What is a reasonable pressure to test? 1.5 bar? And for how long should it hold it?

Not sure whether to leave it overnight or if 10 minutes is good enough?

Cheers.

Also, pic attached of what happens with the non-genuine caps! I think this was advertised as a BMW cap recommended by someone on here!