There is a part of me that wonders if the incidents of DPFs cracking could be greatly reduced if people knew their car was going through a regen and knew to NOT shut the engine off until the regen completes.
I know of a couple TDI owners who use a scan gauge to readout, among other things, EGT. Probably EGT 2, the first one after the turbo. Temp will consistently be above 1100 F/600 C even under light load driving. The owners in question will let the car continue to idle until the temperature drops to about 450 F (down from a high above 1100) and then shut it down. It certainly is a gentler change in temperature when you allow the car to do this.
This not only would be better for the DPF, but much better for the turbo as well. I suspect those that take these precautions will get much better service life out of these components.
Unfortunately, Volkswagen, in their infinite wisdom, decided not to include a warning light to let drivers know when the car is actively performing a regen. Part of the whole "dumbing down" so already distracted drivers don't have anything else to worry about. The DPF warning light on VWs only comes on when the soot loading has gotten critical because too many attempted regens were not allowed to finish (short trips). A simple software reflash could fix that to simply turn on the regen light whenever the car was actively going through a regen cycle, and the cars with message warning systems in the cluster could also advise to keep the car running until instructed to shut it off...
I have a feeling if they did that, and owners actually heeded the warnings, there would be fewer failures.
