Posted 25th June 2012 at 08:03 PM by bimmerule
Had occasional B2/B3 codes with black soot inside exhaust tips along with 75C cruise temp. I suspected rich running and had NEM replace thermostat, twice, but no change. Car threw 69 code, I decided to tackle it myself, took off plenum, vanos lines, replaced tstat and metal seal inside tstat housing using 2 jaw puller and seal driver, leak free on first set of o-rings! Temp now rock steady 4~5C higher than before, black soot disappeared from exhaust tips. Will verify further when it gets colder....