When the engine and transmission were out of the 164 almost two years ago for a new throw out bearing and 72 other items. I pulled the CV joints off, cleaned them up and re-greased them with Liqui Moly as recommended by ChazzyD. My left front hydraulically dampened strut started leaking and had to be replaced a few months ago. For a while now, I've noticed a 'Whurring' sound that seems to be coming from the same left front corner. It sounds like a few small ropes got wrapped around the drive shaft and were flailing around inside the wheel well...
Much to my surprise, today when I jacked the front of the car off the ground and spun both wheels they were silky smooth and quiet -no ropes either. Using jack stands to keep the front tires off the ground, the engine was started and first and second gears were selected. The tires again turned, quiet and smooth, unlike what I was expecting.
It only took me about 7 months to figure out that the three nuts that hold the strut in the front fender were loose. The sound was pretty bad at times and eventually it dawned on me to check the torque on those three Nylock nuts under the black rubber cover, under the hood on each fender. The torque spec. is pretty low. I suspect they were never tight enough. With the nuts torqued to 15 ft-lbs. the front end is quiet and happy again -except when backing out of the garage and turning, it still goes 'thunk'!