Car makes a loud noise when starting

Hello,

Can you explain a little more of what the noise sounds like?

Here is a helpful guide on engine noises:

https://www.2carpros.com/articles/engine-noises

If you would please upload a video of the startup, this way we have a better understanding of the noise you are heating?

As for having a bad valve cover gasket it won't make any noise. It will leak oil, but noise is not one of the symptoms.
Do you know if you are losing oil?

A bad motor mount can create clunking noise while the vehicle is put on drive or reverse. It can also create vibration.

Please let me know if you have any questions.
Thank you.