I just got done replacing the headgasket on a 91 e300 4matic wagon with 188,000 miles on her. The oil in the coolant is a mess. I drained it by the peacock on the radiator and got some oil out but not much. I started her up yesterday and the TEMP GAUGE is not working and she seems to be running hot. So I shut her down. How do I properly flush her and get rid of the oil?? I see that some people suggest tide with water but I need to know specificly how are they doing it. Thank you in advance