I took the car out lastnight and after a short time the passenger side fan came on and stayed on even tho the temp gauge was only half way(where it usually is)
I thought it was a thermostat problem so drained the system fitted a new thermostat and refilled with coolant....still the same thing, after a while the fan comes on so i thought Airlock. Drained the system again done some research on this forum and decided to refill by taking the turbo hose off of the header tank and fill the system through the turbo.
I now have a coolant leak somewhere but cant trace it. On idle it doesnt leak but on a short drive it does. The left side cam cover is covered in water and water is leaking over the exhaust headers, i checked the turbo water lines and it doesnt appear to be from there so now im stuck, out of ideas. Also the system isnt pressurised which i take is because of the leak, the heater works fine blowing nice hot air.


Any ideas? the car is a V3 sti

 

My father had the exact same problem only last month. and the cause was a hairline crack in the alloy header tank which u couldn't see but showed up only on a pressure test.
id get it pressured tested