Thread: 85 v8 county overcooling ideas please

Hi all,
we went away for a family weekend in the new to me 1985 3.5lt v8 county.
Before the weekend the engine was not reaching operating temp so I changed the thermostat to a 82 c from the 74c that was in it. In the garage it brought the temp up nicely.
We went up to Woods point and on the way home the engine was behaving terribly the temp was just above full cold it would not idle, the outside ambient was about 3c. I pulled up in the fog and dark at Eildon and the engine was cold the top rad hose was hard and there wasn't a spot that I couldn't put my hand on the engine. We pushed on and made it home.
I looked today and thought maybe the raised heater intake on the guard forcing freezing air through the heater matrix maybe the cause.
I had the heater turned off and going uphill under load brought the temp up and the engine felt good, coasting downhill the temp would drop and it would fart and carry on, not the usual complaint from a rover v8.
Any thoughts and ideas will be appreciated.
Regards,
Michael.

That's what I thought was happening to the one that was in it, so I replaced it, I tested the new and the old before fitting.
85 county's have a specific heating cooling set up that relies on engine vacuum that is not operational at the moment in regard to opening and closing the heater valves. So I can not shut off the outside air from coming through the heater matrix.