Scorpioy - Sorry I didn't realize it, but you made several comments on the thermostat thread, so you're obviously familiar with all that stuff.

Was the EGR cooler producing soot before or after you worked on the thermostat? I sure hope it was leaking before doing the work - otherwise the thermostat work with possible resultant misalignment of the EGR brackets/bolts might be part of the reason for the cracking. Of course, as noted, there are a bunch of stories of de novo cracked EGR coolers, so hard to know what the exact cause is/was.

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Stephen
2010 e70 35d- now driven by son #2
2005 e53 3.0 - now driven by son #1
2021 G05 45e PHEV - now driven by me
2008 ML320 CDI - driven by wife