Is it normal mechanic got my number off the computer and texted me?

That's creepy. He's probably just socially awkward though, hopefully it's that and not that he's a major creep.
Either way I think that most people understand that chatting a customer - or whatever you call it - up privately is very strange and a misuse of their private information.

Possibly OK; but, borderline.

First; he was indeed trained to get your number into the business computer system. So; it's OK that he asked for your number and entered it into the computer system.

As for personal use of that information for any reason???? That's a grey area. Some companies have policies that their employees cannot use such phone numbers for personal use; others do not.

At the same time... He may have really liked you and wanted to know if you were potentially interested in him. He may also not have good social skills and is doing his best.

IF all he did was send you a text asking if you were interested in starting some kind of relationship - or shared an interest. And then responded appropriately to your answer. I'd say it was OK.

Ideally, he should have asked you while you were in the shop if he could text you.

Some really great relationships have started between client - employee contact.

If they continue to pester you beyond your obvious lack of interest (I assume that you sent him a text saying you have no interest) that is not a good situation. In that case I would text them that unless they stop that you will report him to the owner of the shop (I assure you that almost all owners will stop the problem immediately). If he is the owner of the shop text him that his unprofessional conduct means that you will be taking your business elsewhere - and provide a negative review of his shop.

I hope this helps,

Not cool. There was a cop doing stuff like that in my area and stalking women. Im going to say maybe he isnt a crazy stalker but it still seems unethical somehow.
Yes i would ask him to stop and if he doesnt let the employer know.

Yeah, that's creepy. I'd let him know you don't appreciate his misuse of personal information. If he gets worse, consider reporting him to his superiors and/or changing mechanics. On the off chance he just made a dumb mistake and is apologetic, then it might be appropriate to cut him some slack. Everyone makes mistakes...

I assume you are a woman?
He was probably sniffing the seat while the car was in his shop.

That's odd, he should of been like fantastic and then been like that's all settled. May I text you sometime? Awkward yes. But better than this

Contact his supervisor and get him fired.

Not normal and unethical.

Block number or just ignore him.

It is unprofessional.