Thanks all who responded and here is about the vehicle and why i'm replacing the head gasket.

it is 94 e320 with 144000 miles and I bought it from ebay several months ago. the seller mentioned it had some oil leaks and it gotten severe and just noticed that sporadically, temp started going up when i was at traffic light or sit in traffic and lowers when it was moving again. before I checked the coolant level, i had to go out to pickup something and it was starting to do same but this time temp wouldn't go down... managed get back home with full heater on but when i got to home, it was hissing and some white smokes were coming out of the back of driver side engine and sprayed lots of engine oil/coolant mix as you can see the pictures.

i noticed there were oil/coolant mix in the thermostat housing and a lot of oil and coolant mix came out when i flushed the radiator... it lead to blown head gasket.

local MB indy shop quoted about $2000+ for the work and i only paid the car for $1600 for a kind of project car and couldn't justify the repair to my wife lol and my skill is somewhat limited to regular oil changes and tranny oil changes... nothing major like head gasket job... so, i'm following the pelican's instruction to do this job but not sure what i need to do with the head once i get it out...