Well I have to admit that i'm one of the guys that's hated on the E-cores here. I've been using AC Delco products on my GM car its whole life. I think they make great parts and have never had any issues with them. I remember when the Delco's switched over to the E-core design. I was doing an oil change and noticed the filter was shorter. It was a PF-47 like the old one so it must still be the right filter I thought. I put it on, it fit, didn't leak and that was that.
I did start to notice that the engine seemed louder once the E-core was on it. I ran the E-core for years all the while hearing a very noticeable cold engine tick that really bothered me. It was years later that I learned about how the E-cores were shorter than the classic AC Delco design and what was in them.
Now I had read all about media blowouts and poor thermal bonding of the end caps and all that but what really got my attention was people over the net (not just here on BITOG) saying they too noticed a louder cold engine tick with the E-core design. I began to look for the old classic designed Delco's again but could not find them. I could only get them from the Dealer (unlike in the USA where they can be bought all over) and the GM Dealers here only sold the E-core designs. I didn't want to order any of the old classic Delco designed filters online (too much of a hassle for me) so I came to this site and asked questions and ultimately switched over to Napa Gold oil filters.
Guess what? Once I switched over to the Napa Gold the loud cold engine tick was completely gone! It kills me to this day to think that I could have eliminated that noise years ago simply by switching over to a different oil filter. Who knows how much wear and tear my engine suffered at the hands of those E-cores. As a big supporter of AC Delco products it angered me that they would switch over to that design.
So there you have it. My story. Poor thermal bonding on the end caps, a plastic core, possible media blowouts, a questionable combo ADBV/Bypass Valve is one thing. All I know is my engine had loud cold engine tick with E-cores and now is quiet without them.