H
Harry
I have an old ('87)Yanmar 2GM20F. I was trying to change the coolant on the "closed" side and ran into some problems.My drain valve is metal (rather than plastic) and when I opened it nothing drained. It's possible the reservoir was empty because the overfill tank was empty and I couldn't see any liquid when I removed the pressure cap. I've also had some overheating problems which I've been able to work through (by running the engine at 3300 RPM out of gear until the alarm silences).It seemed no matter how many revolutions, I couldn't get the drain valve removed. Should I be able to? Also, it never closed completely. I could still be there today trying to shut it. It just keeps turning.After I filled the overflow and reservoir, I ran the engine at 1000 RPM for 10 minutes. The level of the overfill tank never changed, and neither did the level of the reservoir. I expected to see the anti-freeze "flowing" like in a car, but it wasn't moving. I also expected to see the level drop when the thermostat opened, but that never happened either. Last, How much anti-freeze (premixed) does the system take? I only used about 2 litres.Any ideas?Thank you.