I was wondering what is the diffrence between a block heater that is installed on a car from the factory and one that you can buy at an autoparts store. Are the dealer ones alot better?

 

not much difference honestly, besides the cost.

 

Depends on the design. Factory block heaters are heating elements that fit into where an expansion plug goes in the block. Aftermarket heaters may be of the design that fits into a radiator hose or like a factory type.

 

What about that magnetic ones that stick onto the oil pan....are they any good?