I just found moine today and it looks as if the cord goes into the block near the oil filter,actually just above it.Does it heat the coolant or engine oil?I have heard both so can someone clear this up for me.Thanks Nick

 

It heats the engine coolant.

 

Yep, coolant.

You can get aftermarket units that warm the oil in the pan. They're common up here north of the 49th, especially in heavy truck appliations.

Waxy