Welcome to ja.com
I hope i can be of help to you today but first i just need to ask you a couple of questions so my answer will be better sourced for you.
1. When the temp gauge goes to hot, if you stop the car but don't turn it off, is the fan in front of the radiator blowing?
2. Also, if the fan isn't going when the temp gauge is in the hot, if you feel the radiator does it feel hot or cold? But please be careful when touching the radiator as if it is hot all over it will burn you. And please be careful of moving parts under the bonnet on the engine.
I look forward to your reply.
Thank you in advance.