Even though this particular query was whether you can use synthetic oil in a (older) VW, the response applies to any older car or truck that’s grown old on a diet of regular engine oil.

Why can I use synthetic oil in my older car?

Generally, the reference to synthetic oil for an engine implies the lubricant is formulated with a polyalphaolefin (PAO) base oil. PAO, which is frequently called synthesized hydrocarbon, is pure and is compatible with