I hate coming across threads with no conclusion when I am searching for advice, so I’m here to put a long overdue pin in this.

Against all odds the M54 seems fine. After getting the engine running I sent an oil sample to Blackstone. They didn’t detect anything anomalous with the sample, just some slightly elevated bearing material compared to their average data (first sample I’ve sent out for this engine).

I’d estimate we’ve put between 500 and 1000 miles on the X5 so far after getting it running again. Coolant temps have been on the money, it runs well, and my main concern is back to the AC and some electrical gremlins.

Thanks to the forum for offering their insights here. Lesson learned to document symptoms better as they are happening (I.e., take a pic of the cluster if it overheats!)