Jim Phillip
Member
Yanmar 240D. Was filling in a ditch and the temp light came on after about 30 minutes. Immediately shut it down and check temps (I keep an infrared in the tool box). Head was about 180 and the block about 165-170. Upper radiator hose was 140ish and lower 125. I had just replaced the overflow bottle and it was clean and clear and right at the fill line. The copper water sensor collar was 175 so a touch cooler than the head. Radiator cap was warm but easily removable after 10 minutes. Started it back up after letting it cool (30 min.) and the light stayed on. Pulled the sensor, nothing visibly broken? and put it back. Started it and the light was out but came back on after about 20 minutes. I assume the sensor is bad? Light goes out of course when I pull the wire off but am unsure if 175 will make the sensor close? Book say it closes at 212? but it didn't seem to be anywhere near that hot and there was no overflow to the bottle.
