As you can tell by the pic, I have a block heater in addition to a drain plug. Block heater is just to the left of drain plug. I don't know if a drain plug sized block heater is available. I was able to remove the "drain plug" by just working it back and forth carefully and oiling till removed. I've never had to replace the heater, but just looking at the size of it leads me to believe that it might be a little more difficult (but not impossible if done carefully with right tools) to remove it or a "plug" that might be in it's place. I hope this helps you, and good luck.....