Diesel - Inline heaters

[roamingyak]

Does anybody have any experience or knowledge of In line Fuel heaters (for
Diesel)?

I'm off to Mongolia for 3-4 months which will also involve going in and out
of Siberia at either end of that period and then travelling through Central
Asia towards India as winter sets in. And sometimes Mongolia skips its
summer which can be cold as the average altitude of the country is 1800
metres.

I have a Land Rover 2.5 n/a diesel and Land Rover do a heater but its at the
engine end, whereas I need something in, on or near the tank end (webasto
engine preheater for the engine side for things). The Russian truck drivers
tend to stay in heated overnight truck stops or light a fire under the tank.
I believe I can also put some petrol into the tank to stop it waxing but
thought I should research a nicer option and then see how it sits in cost
wise.

Any thoughts or insults welcome...