Right -- I thought for sure I had a rod knock -- it sounded just like one-- until I finally put my hand on the hood. That was, yes, a big relief.
And yeah, I tend to go crazy with a marker or a label-maker; I have so many different machines I finally decided to label stuff so I wouldn't have to trial-and-error for the right size wrench or socket. There are a number of things I may only do once a year and I just don't remember what size bolt or wrench I need. RV sacrificial anode? Written right there -- 1-1/16" socket. Lug nuts on my VW TDI? Right inside under the hood: 17MM @ 85 ft-lbs... etc etc. Also put dates on a lot of stuff, like oil filters (plus mileage or hrs), starting batteries, air filters... you get the idea. My good ol' OCD making itself known....