Mine goes into the coolant manifold behind the water pump. A 2000w generator might do it – there’s no start up capacitor draw like a microwave.
In winter below 30 degrees, mine will warm the block to 75 degrees after about 3 hours I guess.
So it doesn’t heat the oil, just the coolant through the engine/radiator.
They need to be immersed and will burn out quickly if you run the engine and it hits an air pocket. I leave mine off for a minute or two before start up.
Check all your wiring carefully – don’t want to electrify your truck!
