Try and hit some fairly high rpm's, not crazy but take it to 4000 at least. Try and get the engine nice and hot. Then after the run pop the hood, leave it running and smell for coolant or oil smells, look for any evidence of coolant on the splash shield (under the turbo and radiator). Let it run for ages and watch the coolant level in the overflow resevoir, make sure it does not go over the max line.