Coolant Problems (again)

Weather was good so it was a good time to have a picnic, so we went to Burghley House on Tuesday.   

Nice day but on the way back I happened to notice the temperature gauge firmly in the red.    Pulled of the road and shut her down.   It sounded like a kettle boiling in the engine.  Sure enough, when I took the bonnet off the system was boiling like mad and coolant was pouring out of the overflow.   After the original problems I have always carried a 2 ltr bottle of water in the passenger footwell.   My only concern was how long I had to wait before I could take off the pressure cap.   I was a bit surprised when I felt the cap and it wasn't hot.   So I risked taking it off, and after a few seconds of releasing the pressure it came off.    So put the 2 ltrs in and started again.   It seemed to be OK but 6 miles from home it shot up into the red again.   Luckily I had stopped in a small village and a friendly house owner filled my bottle up for me and that was enough to get me home.   So I have kept up my record of never arriving home on the back of a rescue truck 😁

So filled her up, using the top of the radiator outlet to make sure I got rid of all the air.   Drove her today, 11 miles each way and the needle didn't even get to the 'N'.    Once she has cooled off I will check the water level and make sure I don't have a new leak.   I hadn't checked the water level for months, so I think it just gradually gone down until it was suddenly below the water pump and the sensor and then it just shot up to the red as the circulation stopped.   That would explain why the pressure cap was cold and also the engine definitely did not feel it was excessively hot.