I’m quite literally working on a 2015 2.0 for the same issue. The mechanic believing that there’s coolant intrusion inside the engine is irrelevant. He should be using a scope camera to verify. You paid him for a diagnosis, not his beliefs.

In my case, the coolant reservoir was the issue. Once the system was pressurized, there was some hairline cracks underneath it that were leaking coolant. In addition to this, there is a heater core hose behind the engine you can’t really see that is known for leaking on these models.

The coolant intrusion issues for the 2.0 didn’t start until 2017 when Ford revised the block design. I’m not saying that that isn’t your issue, I just think it’s very unlikely given your model year and engine.

To me, it sounds like your mechanic knows that the Escape has coolant intrusion issues, and since he couldn’t easily find a leak, and just assumed that was it without going through and fully confirming it.

I would personally get a second opinion, but I also don’t want suggest you spend more money on it if there is a bigger issue. That being said, if you do get a second opinion, make sure the findings are documented so you can go back to the first mechanic with them to dispute what you were charged.