The thermostat on my VX Commodore will move down a little bit when going down hills in cold weather. I thought that the temperature gauge should always stay the same to keep the engine at appropriate operating temp. Is it acceptable to go up and down with hills? The temp gauge sits between 1/4 and 1/2 on the scale. Is this where it should sit for a VX?
The important thing about where the needle sits is not so much where it sits on the scale, but that it’s always in that position. In other words you need to be concerned if it suddenly starts to sit in a different position to normal. I wouldn’t expect the needle to move much going up or down hills, normally they stay pretty much in the same position. Check that the thermostat is the correct one, and that it’s not stuck.