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.

The compensation board in the instrument cluster can sometimes produce this effect- intermittant temperature readings. Actually the board isn't even necessary to gauge function, it just smooths out the operation and knocks the temperory high and low readings down. Sometimes removing the board, cleaning the contacts and refitting it will fix it while some people just remove them and solder a jumper to restore function of the gauge.

Getting to the board requires removing the instrument cluster from the car. If you want the procedure for running without a compensation board email me for the text file.

BTW if your truck is a Ford there is a nice site for help at:

http://www.ford-trucks.com/ (link below)

Randy

Thanks Randy, I will try cleaning the contacts.