I have my 20v installed and running in my ae86 2 weeks ago, and the coolant is always dirty, I changed the coolant once but it became very dirty again after driving for a week, and the water smell like shit too. I then drained the radiator again and put plain water in, it became dirty slowly, and run the engine a day after its all blown in colour. I can't justify if its oil but I think its not as I guess water and oil don't mix. what should I do? should I bring the car to professional to flush it or anyone reckon its cracked headgasket and oil leaking into it?
also, today the car overheated because of thermostat blocked by the dirt, how do I clean the thermostat without pulling everything apart?(I'm using orginal fwd waterline and the thermostat housing is at the back of the head so without pulling the motor out I won't be able to get access to the thermostat, anyway the thermostat was new when I drop the motor in)