There is a cylindrical indentation in the block proximate to the starter motor.
Toyota tacoma block heater cord.
Left side of engine block under connector for spark plug wire.
They are quite expensive but look far better.
They are 450 1 5 hours labour.
Coat core hole and cartridge heater body only not terminals with nscg silicone grease g 624 to ensure good temperature transfer and prevent moisture salt splash from entering hole.
The block heater slides into the opening and then clips secure.
Then you simply connect the plug in place and route the wire to the front of the grill.
I m 90 sure you can run the old style from aftermarket but i havent seen one installed in a tacoma yet.
Job is made easier if.
The block heater is about 100 can at the dealer and comes with a bit of grease.