When I search a pdf version of the 2009 Owner's Manual, I find two instances of the word "synthetic", both relate to seat material. Pictures are a pain right now, but I've copied and pasted: Synthetic leather areas ● Remove loose dirt using a vacuum cleaner. ● Apply a mild soap solution to the synthetic leather using a sponge or soft cloth. ● Allow the solution to soak in for a few minutes. Remove the dirt and wipe off the solution with a clean, damp cloth. Similarly with "conventional", there are several instances on multiple pages, none of them related to motor oil.
Never mind, you are right, sort of: In the 2013 Avalon Hybrid owner's manual it says: 0W-20 only comes in synthetic or synthetic blend that I know of. The term "mineral oil" is where I got confused and thought it was saying conventional vs. synthetic. Note that in the same manual there are other reasons for changing the oil sooner, even if it's using 0W-20 motor oil.
Unfortunately PDF searches are not always reliable. A PDF file contains a series of glyphs, not a series of letters. While in English most glyphs are one to one with their letters, some glyphs in some fonts are composed of two letters (a ligature). The search field may or may not convert the search text into a series of glyphs with a similar ligature. If it doesn't then the word may be present in the text (as seen by a reader) but also not present in the text (by a search). Strange Occurrence With "ti" when printed to PDF - English - Ask LibreOffice "ti" is a common ligature. The presence of a ligature can vary from one font to another within the same document, or even vary within the same font if the letter spacing is forced to spread out the letters more than in usual text. Some PDF printers have an option to disable ligatures, which may or may not always work: How to avoid Chrome "Save as PDF" encoding "fi" etc. as ligatures? - Super User Searching for "oil" as a whole word only might be more reliable, as I don't think there are ever any ligatures in it.