The window is grasped by a clamp at the bottom of the pane. That might a little loose, which would let the window go down, but jam part way up. The rear vertical track of the window can generate a high resistance if not lubed with something like silicone spray. Then, if the window is loose and rotates, it can jam in that track. Try lubing that track first of all before doing anything else. Check the track for damage.
Or, there is something loose with the regulator mechanism itself, causing that clamp to jam on something.
Or, as Steve mentions, there may be something wrong with the big plastic gear in the gearbox attached to the motor, usually it does make noise. Also as he mentions, the window can seem a little loose when part way down. If the gear is damaged, you will have to find a used complete regulator from a wrecked 164, same door location, as the regulator mechanisms are unique for each door as I recall. The plastic gear itself can be replaced from another regulator from a different door if it is from the same vintage 164 if one chooses to rebuild the original regulator. You have to slightly modify (cut a couple of slots) the gear to remove it from the integral cable and install it in the original gearbox. I've done this with a used set as a trial run.
You will have to take the inside door panel off to see what is hanging up as you try the switch. Hopefully it is only something loose in the door, a loose fastener, etc.
BTW, the regulator is easy to change if you have to do that. Is tricky, though and takes fiddling around to get it oriented to come out the access hole. The window needs to be part way down to release the clamp, and then held up with duct tape or a wedge (or both) to keep it clear of the mechanism as that is removed and reinstalled.
1989 Milano, Shankle Sport
1991 164S, stock
1994 164LS (~Q)
1972 Morgan 27
previously owned since 1964:
62 Morris MiniMinor 850, 67 Austin 1275 Cooper S (Downton 3/4 race), 64 Giulia Sprint GT (1st red one made), 72 Fiat 128 Sedan, 75 Alfetta Sedan, 78 Alfetta Sedan, 78 GTV, 81 GTV6, 86 GTV6
Last edited by Del; 07-20-2015 at 11:30 AM.