started getting harder to start, would have to let glow longer and longer, then one day it wouldnt start, after trying for some time the batteryseemed to go down, so i hooked up the jumper cables to my truck, the mercedes started up pretty quick with the cables attached. ran and started good for a week and now no start period, cables or no, i plugged in the block heater for a couple days - no start, not really coughing or sputtering when cranking maybe a tiny bit just for a second. no smoke that ive noticed while cranking.