Morning all.

Purchased an M reg Audi 80 TDI at the weekend. Went to check the coolant yesterday and found a rather dirty and brown sludgy coolant tank, i couldn't see any oil or smell exhaust gasses so I whipped the bottle off and drained and tried to clean the best I could. I wanted to drain the radiator but I couldn't seem to find a drain plug anywhere. It also looks like the car is running at too low a temp, about 50 on the temp gauge so I am thinking stuck open thermostat? Is this easy to change as I noticed there are no Haynes books on this model?

Anyway any help greatly appreciated.

Thanks.