Ineos Grenadier MPG at a glance

The Ineos Grenadier is a proper, body-on-frame 4x4 built for serious work and adventure — and its fuel economy reflects that purpose. With a kerb weight approaching 2.7 tonnes, permanent four-wheel drive, boxy aerodynamics and BMW-sourced 3.0-litre inline-six engines, this isn't a vehicle engineered for sipping fuel. Officially, most Grenadiers sit somewhere between 19 and 28 mpg on the WLTP combined cycle, depending on engine and specification. In the real world, owners typically report figures in the low-to-mid 20s for the diesel and high teens to low 20s for the petrol.

If you're cross-shopping the Grenadier against a Defender, G-Wagen or Land Cruiser, the fuel numbers are broadly in the same ballpark. Anyone hoping for hybrid-like economy from a vehicle of this size and character is looking in the wrong place — but for what it delivers in capability and durability, most owners consider the MPG a fair trade.

Official WLTP fuel economy figures

All Grenadiers use turbocharged 3.0-litre BMW straight-six engines paired with a ZF eight-speed automatic gearbox and full-time four-wheel drive with a two-speed transfer case. Both petrol and diesel options are certified under the WLTP (Worldwide Harmonised Light Vehicles Test Procedure), which gives a more realistic picture than the old NEDC figures — though real-world results can still differ.

Petrol 3.0L inline-six MPG

The petrol B58 engine produces around 281 bhp and 331 lb-ft of torque. Ineos quotes a WLTP combined figure of roughly 19–20 mpg for the Station Wagon, with urban driving dropping into the mid-teens and extra-urban cycles nudging just above 22 mpg. CO2 emissions sit around the 325 g/km mark, which places it firmly in the top VED bracket. The petrol is the more refined and free-revving of the two, but there's no escaping that regular use will mean frequent visits to the pump.

Diesel 3.0L inline-six MPG

The diesel B57 engine offers 245 bhp and a much stronger 406 lb-ft of torque, making it the more economical choice for most buyers. Official WLTP combined figures come in at around 27–28 mpg, with extra-urban runs capable of touching 30 mpg on paper. CO2 emissions of roughly 270 g/km are still high by modern car standards, but noticeably better than the petrol. For anyone planning to cover significant mileage, tow regularly or use the Grenadier as a genuine workhorse, the diesel is the sensible pick.

Real-world MPG: what owners actually report

WLTP figures are a useful starting point, but the Grenadier's real-world economy depends heavily on how — and where — you drive it. Owner forums, road tests and long-term reviews paint a fairly consistent picture: the diesel comfortably returns 24–28 mpg in mixed driving, while the petrol typically manages 17–21 mpg. Tyre choice, roof racks, wading kits and other accessories all take their toll, and the Grenadier's brick-like aerodynamics mean speed has a bigger impact on consumption than it would on a more slippery SUV.

Motorway driving

Motorway cruising is where the Grenadier's shape works against it. At a steady 60 mph the diesel can achieve close to its official figure — some owners report 28–30 mpg on gentle A-road runs. Push on to 70 mph and beyond, however, and consumption climbs quickly; expect 24–26 mpg for the diesel and around 20 mpg for the petrol. Fitting all-terrain tyres, which many buyers do, typically knocks another 1–2 mpg off these numbers due to increased rolling resistance and noise.

Off-road and towing

Off-road use, low-range work and towing all have a significant impact. Crawling through mud, sand or rocks in low ratio can see economy fall into single figures for short periods, though this is normal for any serious 4x4. Towing a 3,500 kg braked trailer — the Grenadier's maximum — will typically halve your motorway economy, with diesel owners reporting 14–17 mpg under load. For lighter caravans or trailers in the 1,500–2,000 kg range, expect around 20–22 mpg from the diesel.

Why the Grenadier's fuel economy is what it is

There are sound engineering reasons the Grenadier drinks fuel the way it does. It uses a traditional ladder-frame chassis rather than a lighter monocoque, solid beam axles front and rear for durability and articulation, and permanent four-wheel drive with mechanical differentials. All of this adds weight and parasitic losses that a modern crossover simply doesn't carry. The upright windscreen, flat sides and boxy rear are dictated by the vehicle's utilitarian brief — good visibility, easy panel replacement and generous interior space — but they create a large frontal area and poor drag coefficient.

Ineos also chose not to offer a hybrid or mild-hybrid system at launch, prioritising simplicity, serviceability and off-road reliability over eco credentials. It's a deliberate philosophy: the Grenadier is designed to be fixable in a farmyard or a remote workshop anywhere in the world, and that comes at the cost of the electrification tricks that boost economy in more road-focused rivals.

How the Grenadier compares to rival 4x4s

Put next to its most obvious competitors, the Grenadier's fuel economy is roughly on par. The Land Rover Defender 110 D300 diesel returns an official 30–32 mpg WLTP, edging the Grenadier by a small margin, while its P400 petrol manages around 25 mpg thanks to mild-hybrid assistance. The Toyota Land Cruiser 300 (where available) sits in similar territory to the diesel Grenadier at around 26–28 mpg. The Mercedes G-Class G400d diesel achieves around 28 mpg, while the petrol G550 and AMG G63 are notably thirstier, often struggling to break 20 mpg in real use.

In short, if you want a full-size, ladder-frame 4x4 with genuine off-road credentials, you're accepting economy in the 20s rather than the 40s. Only a Defender with the P400e plug-in hybrid drivetrain significantly changes the equation, and that comes with its own compromises around load space, weight and battery range.

Tips to improve your Grenadier's MPG

There are practical steps that can meaningfully improve real-world consumption. Sticking to standard road-biased tyres rather than aggressive all-terrains can be worth 2–3 mpg on the motorway. Keeping tyre pressures at the recommended settings, removing roof racks, ladders and wading snorkels when they aren't needed, and avoiding unnecessary weight in the load bay all help. Driving style matters too: the Grenadier rewards a relaxed, torque-riding approach — short-shifting the automatic and cruising at 60–65 mph rather than 75–80 mph can add several mpg to a long journey.

Regular servicing, clean air filters and fresh engine oil also make a measurable difference on a hard-working diesel. If you spend most of your time on tarmac, consider whether you really need the aggressive off-road tyres many owners fit for the look — road tyres will improve economy, refinement and braking.

Is the Grenadier's fuel economy a dealbreaker?

For most buyers who understand what the Grenadier is, the answer is no. This is a working 4x4 built to a very specific brief: rugged, honest, mechanically straightforward and genuinely capable off-road. Its fuel consumption is a natural consequence of that engineering, and it's in line with — or better than — much of its direct competition. If you need a vehicle that can tow 3.5 tonnes, cross a river, climb a mountain track and still take the family to the shops, low-20s mpg is a reasonable price to pay.

Where the Grenadier's economy might genuinely matter is for buyers doing very high annual mileages on motorways, or those who need company-car friendly emissions — in both cases, a Defender PHEV or a large diesel SUV like an Audi Q7 or BMW X5 will be significantly cheaper to run. But for the farmer, the expedition traveller, the tradesperson working on tough sites, or the enthusiast who simply wants a proper old-school 4x4, the Grenadier's MPG is part of the package, not a reason to walk away.

FAQs

What MPG does the Ineos Grenadier actually achieve in real-world driving?
Most diesel Grenadier owners report 24–28 mpg in mixed real-world use, with steady A-road cruising occasionally touching 30 mpg. The petrol typically returns 17–21 mpg in everyday driving. Towing, off-road use and aggressive all-terrain tyres will reduce these figures noticeably, while gentle motorway driving at 60–65 mph will improve them.

Is the diesel or petrol Grenadier more economical?
The diesel is significantly more economical. Its official WLTP combined figure is around 27–28 mpg compared to roughly 19–20 mpg for the petrol, and the diesel's stronger torque means it works less hard under load or when towing. For most UK buyers, especially those covering higher mileages, the diesel is the sensible choice.

How much does towing affect the Grenadier's fuel economy?
Towing has a major impact. Pulling a heavy braked trailer close to the Grenadier's 3,500 kg maximum will often halve motorway economy, with diesel owners reporting 14–17 mpg under full load. Lighter loads in the 1,500–2,000 kg range are more manageable, typically returning around 20–22 mpg from the diesel.

How does the Grenadier's MPG compare to a Land Rover Defender?
The Defender 110 D300 diesel is marginally more efficient on paper at around 30–32 mpg WLTP versus the Grenadier's 27–28 mpg, and the Defender P400e plug-in hybrid can be dramatically cheaper to run on short journeys. However, in like-for-like non-hybrid form, the two vehicles are very close in real-world consumption, and the Grenadier's simpler mechanical layout appeals to buyers who prioritise durability over the latest efficiency tech.