you'll need one with the block heater option, or you won't be able to switch your engine off at night, or in the day!
Below -40 strange things start to happen as some have suggested above. Steel will snap, rubber becomes solid and brittle and you can get that moment of great comedy as you try and set off and your wheels go round but your tyres stay put! The key thing though is to never let the vehicle get cold, or it won't start and things will break.

Hi Moggy

Yep, I will just keep the engine running 24 hrs a day (unless I find a heated garage for a night etc), and will probably leave the transfer in neutral and the gearbox in gear to keep the oil moving around and put a little more load on the engine.

I've actually decided against a heater as it's too much hassle to get an extra fuel tank / gas cylinder, extra battery and all the associated wiring and split charger, just for a week or so at / below -40ºC, I just don't have time to do it all before my intended departure date.

I know that people drive cars in -50ºC so I hope mine won't snap :D The biggest problem I forsee is icing up of the windows inside the car if I sleep in it in those temperatures. I'm currently putting in foil-covered foam insulation beneath all the carpets and behind the trim panels, and I plan on covering all the windows except the windscreen and front side windows with it semi permanently, and having removable ones for the windscreen and front side windows.

Studded tyres will be a must, and decent equipment; my tried and tested -40ºC sleeping bag (was still toasty warm sleeping on the ground with no tent in -20ºC in Mongolia), high altitude climbing parka / salopettes and good base and mid layers.

And emergency vodka.

Cheers!

EO

Ebersabacher ( hydroponic ) come in two basic sizes . 5kw and 10kw.

5kw is more than enough to heat most vehicles.

However, at high altitude they only run at about 30 % so this is the figure you need to look at when deciding.

In addition the 5kw will need an altitude compensator kit which cost nearly as much as the the heater itself.
The 10kw m10 has an altitude compensator built in.

When I bought mine it actually worked out cheaper to it the bigger one.

I am confident that if it runs at only 3kw at altitude it will cope.

In addition the 5 kw runs at full belt or half (2.5 )

The 10 kw can tick over much lower at 1.5 kw and more increments up to the full 10 kw.

This makes the 10kw more fuel efficient.

I use mine to also pre heat the engine ( Mercedes 5.9 lt cast iron block )

In a recent test it started at about minus 15 and after 20 mins the engine temp was at about plus 40 degrees. I was very pleased with this result.

I'm not suggesting that the 5kw isn't a brilliant heater, I am merely suggesting that the 10 kw is also a major option .

Neil

Cloud 9 is Born

Right, time for an update...

Trip did not happen this year as the truck was nowhere near ready... but it is going ahead next year.

Truck is now all working nicely, I have done a lot more cold weather and route research. Will be running super soft studded winter tyres with tubes, all synthetic oils (0W-20 in the engine), double windscreen...

But still have to take the plunge and buy a cabin heater.

For reference, I am getting a cabin air heater, not a block / coolant heater. As said, engine will stay running at below -35 if there is no heated garage. I will have some serious fuel supplies (preferably 250 - 300 litres of petrol I.m assuming 20 to 25 l per 100 km fuel consumption averaged).

The cabin heater is over EUR 1000 so I really want to make sure I am making the right choice.

I am planning on buying a petrol (gasoline) heater, which seems to limit me to Webasto, as Eberspacher seem only to have petrol block heaters. Altitude is not really an issue as I don't foresee being much above 1200 m on this trip, and usually much less.

I have bought a split charging kit which is ready to go in. I will get a second battery... not sure what to go for though, a cheap Hankook 110Ah leisure battery, or an Optima Yellow Top 55Ah battery which is twice the price?? I've had Yellow Tops before and they were awesome, (though I have switched to an Odyssey battery for the main starter; 900 CCA vs 750 on the Optima) but is there any reason not to go for the cheaper Hankook battery?

I will run the heater from a separate fuel tank. This means I can use 80 RON petrol (yes, you can still get it in Russia, I've seen down to 68 RON even!) which will be better for the heater (more rapid combustion). It also means that I could go for a diesel if it were advantageous? It would certainly save some money.

So is there anything I am missing? Any final recommendations before I take the plunge?

Thanks a lot!

EO