wanted to buy: Honda block heater for a 1993 Accord EX-R. I can't seem to locate a genuine Honda block heater. My mechanic tells me that aftermarket block heaters may not fit properly and might pop out in extreme cold. Apparently in southern Ontario the aftermarket block heater might work but in northern Saskatchewan (where I'm headed this winter) the plug might pop out. Is this any truth to this? any help would be appreciated,