I have a 2002 Ford F-250 with the v10. I had a guy that works for a ford dealership, that rents a garage replace my exhaust manifolds. He said that they had been replaced before there were a lot of broken bolts and helicoils that he had to remove. So I get it back looks good, sounds even better. I take it to work and back about a 30 mile round trip. Then take it plant shopping the next day about 50 mile round trip. No leaks I park in a garage, so I check daily for leaks on my cars. I take a lil bigger trip the following day to help a friend 35 miles one way. I load the truck up with some light stuff, and drive home. I am always easy on my cars and trucks, didn't even get above 3 rpms. So I got home heard a hissing noise and noticed coolant coming outta a manifold bolt. I think he might have just drilled to deep. Curious what kinda repair this is gonna be? Any suggestions on what I should do?

 

I'd take it back to the mechanic.

They should have been replaced with exhaust studs, and if drilled into a coolant jacket,, depending on if a bolt used or stud, a shouldered stud with a good setting sealer should seal the leak. If a thread insert installed along with a bolt or stud, increases the possibility of a leak more so since the original hole had to be drilled a larger diameter to accept the thread insert and drill depth can be an issue going larger in diameter., but generally if a stud and a metalized sealant etc used it shouldn't leak.
When a thread insert is used on a now 'open' hole, doubles the chance of a two sided thread seepage. Generally just an anti seize is applied on blind holes and studs on insert, tightened against their shoulder.
Might try and re torque the mounting nuts/bolts and see if it stops. May require the manifold be removed to address the leaker. As long as a quality job of getting the old broken studs out was achieved, shouldn't be a huge issue stopping the leak..