It doesn't sound as if your mechanic is as clued up as you believe, unless it was an honest mistake he made and he paid for the rework on repairs 2 and 3.

If it is freezing up, then there is condensate there to freeze. An additional pressure relief valve could freeze up just like the CCV system does, as it serves the same purpose. And an additional valve wouldn't address the risk of the valve freezing in the open position, and drawing oil from the sump into the intake.

Sounds like the system needs to be returned to the original design, and all cleaned out. It doesn't sound like all the lines were cleaned out when your mechanic worked on it, and that the condensate in the lines just moved on down to the CCV to freeze again. Just guessing here, it is hard to diagnose over the web.

I wouldn't be trying to redesign it. The vehicle is 12 years old. It has been through 12 winters. Problems that show up after 12 years are not generally considered design issues, they are much more likely to be maintenance issues.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
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