I am changing my vacuum hoses under the intake manifold. I was expected to find a little hardened CBU to scrape off. Mine is wet and wipes off with a paper towel. Is that normal? My 35d is odd in that it was only driven 25k miles between 2009 and 2015. It has 45k miles on it now.


UPDATE. After several months of troubleshooting I found out my X5 was running on old software. The newer software from 2011 is designed to work with the new style EGR valve to limit CBU buildup. So don't look at these pictures and think this is normal for a 2009.

2022 update. M57 now has 110k miles. CBU was removed around 50k miles. Just pulled the intake to do the valve cover gasket and there was little to no CBU after 60k+ miles. The new software and egr is preventing the CBU nicely.

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2009 35d, 2006 325i & 330i