Is your Isuzu D-Max wasting fuel? Simple driving tips to fix it!
Is your Isuzu D-Max guzzling diesel like a Springbok supporter drinks brandy after a World Cup rugby match? It's time to look into this problem. Here are a few reasons why there may be an issue with high diesel consumption, and we show you how to fix it, too.
How to improve fuel efficiency in your Isuzu D-Max
For good reason, your D-Max is one of South Africa's most popular bakkies: these Japanese workhorses and leisure bakkies are built to last and sip diesel sensibly. But if your fuel gauge drops faster than your faith in politicians, you might be doing something wrong. Let's fix that wallet-draining problem with some proven fuel consumption tips!
Related: Isuzu 1.9 X-Rider 4x4 A/T Review (2024)
Isuzu D-Max diesel engines
First things first - know your engine and what it should be consuming. Isuzu offers two main diesel powerplants in the South African D-Max range:
1.9TD diesel engine:
- Power: 110kW
- Torque: 350Nm
- Isuzu claims: 7.6 L/100km
- Real-world fuel consumption: Up to 9.4 L/100km (mixed driving)
- Found in: X-Rider models, various single and double cab variants
3.0TD diesel engine:
- Power: 140kW
- Torque: 450Nm
- Isuzu claims: 8.1 L/100km
- Real-world fuel consumption: 9.0 L/100km (mixed driving)
- Found in: Higher-spec double cab models, V-Cross variants
Notice the gap between claimed and actual fuel consumption? That's not unusual; most manufacturers' figures are overambitious. The real-world numbers from the AutoTrader team's Isuzu reviews show what you should expect when driving like a normal human.
Important note: 4x4 models will always consume more fuel than their 2WD counterparts due to the additional weight of the low-range transfer case, front differential, and drivetrain components. Expect an extra 0.5-1.0 L/100km compared to 2WD models, even when driving in 2WD mode.
Isuzu D-Max 3.0 Double Cb 4x4 V-Cross (2025) Quick Review
How to tell if your D-Max is wasting diesel
Based on our reviews and personal experience, here's when you should start worrying about poor fuel efficiency:
1.9TD models: If you're consistently seeing more than 11-12 L/100km in mixed driving
3.0TD models: If you're regularly using more than 10.8-12 L/100km without heavy loads
If fuel consumption creeps into these danger zones, your driving style or bakkie (or both!) needs attention.
(The Isuzu KB250 my husband owned remained low on diesel despite towing a heavy trailer for thousands of kilometres.)
Related: Isuzu mu-X (2024) Quick Review
Common fuel-wasting mistakes D-Max owners make
Warming up your car
Stop letting your D-Max idle like a pensioner at a traffic light! Modern diesels don't need those marathon warm-up sessions your father insisted on. A minute or two is plenty, even on those crisp Highveld mornings. Extended idling just burns fuel without moving you anywhere.
The "I paid for all the horses" syndrome
Yes, that torque feels satisfying when you plant your right foot, but diesel engines are happiest when treated with respect. Think of it like a good braai: low and slow wins the race, not aggressive heat that burns everything. (Unless it's a steak fire.)
The forgetful four-wheel-driver
Here's a big one: driving in 4WD when you don't need to. Many D-Max owners forget to switch back to 2WD after tackling that farm road or beach access. Leaving it in 4WD on tar roads can add 1-2 L/100km to your consumption - that's real money over a month of driving.
Isuzu D-Max 3.0TD double cab AT35 4x4 (2024) Review
Driving tips to improve your D-Max fuel efficiency
Find and stick to the efficiency sweet spot
Based on actual testing, both D-Max engines have a sweet spot where they sip fuel rather than gulp it:
For the 1.9TD, Keep revs between 1 800 and 2 200 r/min during cruising. Push it beyond 2 500 rpm regularly, and watch the fuel gauge reach empty quickly.
For the 3.0TD, this bigger engine is happiest between 1 600 and 2 000 r/min. Use that generous torque to maintain momentum rather than for traffic light drag races.
How to save diesel on the highway
Most D-Max owners accidentally discover this: both engines hit their fuel efficiency peak around 110 km/h. Push beyond 120 km/h and watch your consumption climb. On highways, cruise control set to 110 km/h can make quite a difference.
Load with care
Your D-Max can carry a tonne, but that doesn't mean it should always look like a mobile hardware store. Every 100kg of extra weight adds roughly 0.3-0.5 L/100km to your consumption. That collection of tools, spare parts, and "just in case" items in your load bay could cost you an extra litre per 100km.
(A few years ago, we hit the Cederberg with the heavily kitted-out D-Max X-Rider, and the 2.5-litre's consumption rose to 12.0 L/100 km. Read about that adventure here.)
2WD vs 4WD: When to employ what
This is crucial for 4x4 D-Max owners: always drive in 2WD unless you actually need 4WD. The system is designed to be switched on-the-fly, so use it:
- 2WD for: Tar roads, good gravel roads, city driving, highway cruising
- 4WD for: Loose sand/gravel roads, muddy farm roads, steep rocky inclines, launching a boat
Forgetting to switch back to 2WD after that weekend camping trip can cost you an extra tank of fuel per month.
D-Max maintenance tips for better fuel efficiency
Air filter: Save diesel with simple maintenance
A clogged air filter can considerably increase your consumption in dusty conditions. Check it regularly and replace it when it looks like it's been through a dust storm.
Tyre pressure tips for fuel efficiency
Under-inflated tyres are silent fuel thieves. Just 0.3 bar lower than it should be can raise your 1.9TD from 9.4 L/100km to over 10 L/100km. Check pressures monthly when tyres are cold, not after driving 50 km to the garage.
Follow these tips for many happy kilometres that won't cost you too dearly.
