850 coolant issue

[mrscottg89]

After driving for a decent amount of time (about 15-30 min maybe 30 miles) my car starts smoking from under the hood, heavy if i sit at idle or slow speeds and same for parking, but only after driving. The temp gauge does not go past halfway and sometimes it will get half way and all of a sudden go back to C? When I shut the car off is when the fun happens the smoke increases for about 10 seconds to a minute or two. The smoke/steam is coming as well as (just found)coolant is coming out from the turbo area under the silver shield and is spilling while the coolant continues to boil if i let some pressure out the coolant will try and spit out and once tightened it will suck back down. any idea what to do?