Running Hot

[Pelham West <pelhamwest@domain.elided>]

I'd be grateful for some advice on this.

I don't tend to use my Stag much over the winter months but take it for a
run every week or so to keep the damp at bay. Yesterday it was quite chilly
outside (about 5 degrees centigrade) when I took the Stag for a spin. After
about 4 miles it was up to normal running temperature - needle just below
centre on guage but then the needle continued to climb slowly  for the rest
of the journey. Back home after a total of 10 miles without stopping, the
needle was at the three-quarters mark.  The radiator felt hot but perhaps
not as hot as I would expect from that sort of temperature reading.

Should I suspect the a thermostat sticking closed or something more
sinister?

Pelham