What units are those numbers?

A standard head gasket on the M54B30 is 0.7 mm thick. That's what comes as the original HG. I had my head surfaced to fix slight warping, that was causing the same problem you seemed to have. After that, I was told that he did not need to remove too much, and that I could replace with a 0.7 mm HG, and that's what I did. Working fine like that.

As far as I know, the only other option is 1.0 mm. I never saw anything bigger than that, although I was not looking for it. I can believe that at some point, a gasket can be too big. For example milling off 1 cm and replacing it with a 1 cm thick gasket would definitely not work, of course. I don't know what the cutoff is, but maybe 1.0 mm is the max for a good reason.

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2001 X5 3.0i, 203k miles, AT, owned since 2014