Engine overheating, leaking coolant when shut off.

I bought the car AS IS and it overheated the day I bought it. White smoke out of the engine. I pulled off the highway and there was a large crack on the top of the radiator. I had the radiator replaced and drove it home about 90 miles. The mechanic said there was also a coolant tank leak, but the tank holds fluid fine, so I'm not sure this is the issue. The car has a bit of smoke coming from the exhaust, but nothing excessive. The car is still overheating though. When the car is switched off after running hot, it makes a gurgling sound and white smoke appears from somewhere close the block. (I must remove the plenum do pinpoint the location) it also drips radiator fluid. The radiator itself gets hot, but the coolant tank does not. The leak seems to be coming from the top of the engine. The last mechanic did not compression test it. Im just wondering if it is possible to rule anything out due to the fact that it doesnt smoke until turned off, does this have anything to do with the waterpump of thermostat? I am hoping it is not the head gasket, because I will have to replace it myself for financial reasons. Thank you!