Cold weather pre-heater

V12-Engine
1

I know this has been covered to some extent. I live in a cool but not really cold place and find that on a 0 to 5C morning that the v12 takes ages to warm up. I’d like to give it a head start.
It seems the options are a sump heater (in the form of a 250w pad that glues to the sump); A circulating coolant heater (via heater hoses vs other connections?)- which seem to be much more powerful and effective (1000w); or simulating jag’s solution of a heater spliced into the bottom rad hose (750w)

If Jag’s radiator hose heater is used, i can see that heated water would rise into the block via the water pump (and maybe into the thermostat housing backwards in the bypasses), but unless the thermostat opens (not likely), there is no circulation back to the radiator- so surely the convection current wont flow long. Am i over-thinking?

2

Most of the XJS I’ve see had built in heater coils in the block and came with 110 VAC connectors.
I still have one or two of the cables in my parts bins if anyone needs one.

3

I’ve not seen a heater in a v12 block, and the parts book shows one in the lower rad hose.
Are the block heaters aftermarket?

4

My 6.0 had one and I’m pretty sure my 4.0 too. I disconnected the cable.
I have seen a number of blocks with them.
Too long ago to remember where the coil is on the blocks.
It can’t be that difficult to find it on the left side looking from the driver seat.