When I bought my slightly used 2000 BMW 528 a few months ago I was
told by the dealer that it had an alloy block. I had read that some
versions were also iron and really preferred an alloy block for weight
and less oil leaks. The service manager confirmed that it was an alloy
M52 TU since it had double Vanos.

After reading the 2000 BMW brochure (purchased from eBay)a few days
ago, it notes that the 540 had alloy in that year, but eludes that the
528i has an iron block.

Short of me climbing under the car with a magnet, how can I tell??

Matthew
00 528i Sport