Within every 1986 Buick Regal that was sold, contained inside the glove box, you could find the owners manual as well as the supplement package, consisting of books like the maintenance schedule, radio & speaker options, warranty info., etc.
Of course, if you didn’t buy your Regal Gbody brand new, well then, you may or may not have received these items with your purchase.
Here’s the buick literature you should have for your 86 model:
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