New battery day! Old battery did not like the sub-zero (F) temperatures last week and the car refused to start.
I took the battery out and brought it inside to thaw out and charge. I looked at the part number online. It was a 3-year-old Interstate, but it's capacity was only 75 amp-hours, which is apparently barely enough for a diesel in cold weather. The new VW branded battery is rated at 80 Ah. According to the dealer, the car's VIN says the bigger battery is correct for the TDI. New battery p/n is 000-915-105 DH DSP.
Bigger it is. 12" long vs about 9" for the old one.
And, I worked on the engine cover. Finally it now has a VW emblem on it! (038 103 940 F) And I modified it so that tools are no longer needed to remove it, just pull up & it pops off.
While it was off, I added some sound damping material to the bottom of the cover. Now I have such material on the bottom of the engine cover & top of the skid plate - no more "rocks in a coffee can" sound that a cold ALH creates at startup on a cold morning. The diesel clatter we know & love is still there, but the raspy-ness is gone.