Listen, this is too much. We all love our Dad's and glad we get to spend time with them when we can. However, the op is not upset mainly with his Dad, just people (dad in this case) who act like they know more just because of age. We all have experiences in this aspect (parent, boss, sibling).
The op clearly has a garage with a nice car. Let us NOT assume we know anyting more than what the OP stated. We do not know he is using this for free, living free rent, free groceries that is unfair and nieve to judge and assume another poster on a forum.
I love this site, mainly for great, objective, supporting people and their experiences and advice. I try not to assume anything and I appreciate it if members would not jump to conclusions about situations. Opinions are respected in this manner.
I was just ribbing about the garage statement, I think the op just needs to talk it out with his father, or anyone else, about his methodology and practice. I know my Dad wishes I could be home to detail in his garage and visit more often, even if I do get a little "fatherly " advice now and again.

rops:
I'm done sorry for the ramble everyone.:nomore:from me
Mark