I bought a couple (for when the 1st breaks) of cheap stethoscopes from HarborFreight. They help find squeaks & rattles. My 85SD has grease fittings on the hinges, not door check.

Replace your door checks if the door doesn't open smooth and easy. I didn't realize how bad mine were. Do all 4 if you plan on keeping the car. No sense having a good perfectly working door that shows how bad the others are.

The good news is you can grease the window regulator while the door card is off for the check. You can also look for something loose if it is in fact your door that is rattling.

__________________
85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.