It appears The Duramax HPCR is or could be suffering the rath of the poor quality ... Worlds biggest Auto maker GM will hopefully make some corrective measures ....
The rest will simply grasp the bull by the horn thru Message Board info and trial and error testers and decide on whats best to use for better filtering systems available in the aftermarket to us ...
Can't wait to get my 2um on when I find the time ...
Mac