Loud engine and coolant leak after motor mount replacement

To make a long story short, I had all three mounts on my car replaced (two engine mounts and one transmission mount). I took it to the mechanic I have been taking my car to for the past couple of years. When I drove the car back home, I noticed the engine was very loud, sounded like a truck! Then when I got home I noticed it was leaking coolant like crazy. I am taking it back to him tomorrow morning but I am curious to see if anyone might know why this happened? He told me he had to remove the lower radiator hose to remove the transmission mount so that explains the leak but I do not understand the very loud engine noise, check out the video.