Installing a cab heater

Being warm in a Defender needn’t rely on a four-season sleeping bag. Alisdair Cusick looks into fitting a diesel heater to banish chills for good

We explain how you can take the chill out of Defender ownership in our step-by-step workshop guide

THE cabin heater in a Defender doesn’t have the greatest of outputs. Working off the engine coolant, it’s only at working temperature when the engine is fully warmed up and running. If your Defender doubles as a camper or overland base, then you’ll need a better heat source than the standard system, which is where auxiliary diesel heaters come in.

Popular in camper conversions, and similar in principle to the gas powered systems used in motorhomes for years, their small size belies the heat they produce. A compact 2kw heater can provide 86 cubic metres of warmed air per hour: more than ample to heat the relatively small cabin space of a 110.

With the majority of Defenders running on diesel, most (but not all) installations simply tap into the host vehicle’s fuel tank for an ample fuel supply.

One brand catering for the Defender market is Wrexham-based Autoterm UK, retailing their Russian-made heaters. With silent fuel pumps, brushless fan motors and a three year warranty, they are used by the Russian military in vehicles operating down to -50˚C. For a Defender, they recommend a 2kw unit, as the harder the heater works, the cleaner it runs. I visited Autoterm to see their fitters, Gareth Story and Mark Law, fit a 2kw system to LRM editor Patrick’s 1998 petrol-engined 110.

Not got a diesel engine? Don’t worry

Most Defenders are diesel models and so the fitters tap into the vehicle’s existing fuel supply using a T-connector in the fuel line on simpler engine systems or, more usually, tapping directly into the fuel tank for a feed.

With a petrol vehicle, like this BMW 2.8 petrol engined Defender (or V8s), a small additional diesel tank is fitted. The mounting, size, and visibility of this tank is totally up to the individual, and may depend on the vehicle’s intended use and/or body design. Fairly obviously, safety concerns abound around fuel, the heater, and exhaust gases from the heater. If in any doubt, use an expert, like Autoterm UK