I start visiting this site about a week ago. It's great. I wish there was one like it for my truck. But this question is about my sisters' 240 DL. Last week I drained the coolant, (it was real rust colored), and ran a few gallons of water through it. I replaced coolant. Temperature didn't decrease. (1/2 way straight and level, close to red line on hill and high speed). I changed the oil, combed the fins. Temperature didn't change. This morning (five days later) the temp. won't rise above 1/4 on the gage. This afternoon I drove it again, and now there is no temperature reading at all. By the way I couldn't have even found the drain cock without this site! Thanks for any help.