Plugged my 82 300 TD in last night using a heavy duty timer set to kick on at 6am. At 10am I went out and felt the engine by the oil cap with my hand. Ice cold. In the past it was always warm. I tested the extension cord and timer and both are working fine. Checked the block heater cord all the way to the block and it looks intact and in good shape. Block heaters are so simple I am wondering what it could be. Am I wrong to expect the top of the engine to be warm after a cold night (20 degrees)?