HelmutK wrote:My printer has recently developed a rattle when printing and over the past week has become louder.
What I found was that the X carriage that supports the white guide blocks, for the rear X guide rod, has cracked.
As a result there is a large gap between the white guide blocks and the rear X guide rod.
The part of the X carriage assembly that supports the nut for the screw for the lower white guide block has cracked.
I am contacting Support to see what they say.
So if you have a rattle in your extruder carriage assembly check for the possibility of having this issue.
I am having a increased 'rattle' in mine as well and even though the white block seems tight I do see a crack in the carriage near the white block.
I hate to continue grumbling but this just adds to the list of issues that I am having and support replys "we'll get right on fixing your issues", but that is as far as it gets, talk and no action.
I do love using the machine even with its issues but I'm thinking that it will have functioning longevity about the same as the Yugo, and we all (or maybe not) remember those. 
Even with all the fun spots, if I had to do this whole experience over again I would pass and look in another direction..... IMHO