I am foreigner and have work permit .

If I buy a car in Bangkok, do I need to do anything in Bangkok transport office?

OR

do I just pay for the car and take the blue book with me?

I do have 2 pages doc that the seller and buy sign that I got from the transport office.

How do I know there is not a loan on the car or a fraudlent blue book?

I assume I get new plates in Phuket Transport office?

thank you for reading and responses

I assume this is a second hand car purchase ?

Should be no problem. Have the seller sign the transfer paper and a witnessed signature of the mandate paper (if seller not accompanying to transport office. Some of sort of receipt for the sale would also be a good idea.

If there a loan out on the vehicle then the company/person loaning the money would also hold the blue book and it's normal for them to have their name added to the book by the transport office.

Fake blue book - no idea about that. But do check that the vehicle chasis number in the book is the same as stamped on the car.

Take the car and book (and original passport & work permit + signed copies) to Phuket transport office, they inspect the vehicle, check the vehicle chassis number, assess the value of the vehicle, you pay the small % transfer tax on the value and re-registration costs, get new Phuket plates, hand in BKK plates.

I do not have a work permit only on tourist visa when arriving back from work. Is it possible for me to do this as well with proof of residency? What I would really like is to finance in my name if possible. Any people gone through with this here who can help ? Thanks ppl

Sure you can do the transfer with a Certificate of Residence from Immigration.

As for finance - on a tourist visa you would need a Thai national as a guarantor.