Possible engine damage, there is a hissing noise coming from the hood, could it be a vacuum leak?

Hi,

A vacuum leak can cause the engine to run differently. If it is a large enough leak, the engine may not start.

What is the vehicle doing? Is it possible for you to record the sound and upload it for me to hear?

Also, here is a link that explains how to locate/fix an engine vacuum leak. Check to see if you can find a possible issue.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Additionally, here is a link that explains common symptoms of a vacuum leak:

https://www.2carpros.com/articles/automotive-engine-vacuum-leak-symptoms

Let me know.

Joe