P38A Runaway temp 2.0

On the way back from Gatwick this evening, the temp shot up to the red (again.. last time this happened a couple of months ago i replaced the t-stat, Viscous fan and waterpump)..

immediately pulled to the side of the dual carriageway, let it cool down, and limped off to the nearest petrol station.. on the way, the temp , idled, then shot up again, as i pulled off the road so the nearside was up the kerb, and the offside on teh road, the change in angle caused the temp to drop back to normal again..

a couple of time in the limp to the petrol station the temp rose and fell off. made it to refuge, let the ewater under pressure cool off and topped up with water.. made it back home with the temp gauge not moving from dead center all the way, even sitting in traffic.

I suspect that this was an airlock that had moved. i'll be watching carfully over the next few days.. anyone any other thoughts ?

fingers crossed mate its just that but maybe pull the plugs n see if any are steam cleaned just to make sure its not a hg problem