I've been avoiding it because I know what is coming, but I'll admit I was the one fool who had a DPF failure with an aftermarket intake... that being said I do not think the intake was a direct cause of the failure, it
may have contributed, but it was not the cause.
The failure progressed this way, at 115k miles I had an exhaust flap valve code come up, after cleaning it a few times I changed it around 117k. I probably put the aftermarket filter on at 120k and by 125k I was throwing EGR codes.
At 140k I gave up on cleaning and replacing the EGRs and took it to my friend at VW which his first question was "How long have you had the K&N filter on there? VW Tech Line says they've seen DPF failures they think are caused by an aftermarket filter"... when I told him it was on for 20k he said they told him it probably was not the cause of the failure but they recommend removing it as soon as possible anyway.
The overall failure was a cracked DPF, I've never had a MAF code or any pre-DPF or EGT sensor codes, the K&N filter was removed after the failure was "repaired".
I am fairly certain that the stuck exhaust flap valve was the main cause of the crack in the DPF, most likely from soot accumulation and high EGTs. The K&N filter
may have contributed to this by altering the air flow or fuel map.
And before this turns into a lecture on the evils of K&N filters we are all well aware of this thread;
http://forums.tdiclub.com/showthread.php?t=290373 unfortunately I only found it well
after I installed the K&N filter.
