If you manage a fleet in New Zealand, you've probably wondered why misfuelling seems to happen more often with diesel vehicles. The statistics tell the story — diesel vehicles account for roughly 80% of all misfuel incidents we handle at EEK Mechanical, and it's not just bad luck.

The main culprit is simple physics. Petrol nozzles fit easily into diesel tanks, but diesel nozzles are specifically designed to be too large for petrol tank openings. This means while it's nearly impossible to put diesel into a petrol vehicle, putting petrol into a diesel vehicle happens regularly at Z Energy, BP, Mobil, and Gull stations across the country.

Several factors make diesel drivers more vulnerable. Many operate company vehicles they're less familiar with, especially when switching between personal petrol cars and work diesel utes or trucks. The morning rush, fatigue after long shifts, and simple autopilot behaviour at the pump all contribute. Add in the fact that petrol pumps are often more accessible and numerous than diesel pumps, and you have a recipe for mistakes.

For fleet operators, the consequences extend beyond the immediate vehicle damage. You're looking at potential downtime, insurance claims, and the domino effect on job schedules. Modern diesel engines with sensitive fuel systems can suffer expensive damage if petrol contaminates the system, particularly if the engine is started.

What to do right now

Implement a simple prevention strategy. Provide fuel cards that only work at diesel pumps, install large diesel-only stickers near fuel caps, and brief drivers during vehicle handovers. Consider fuel management systems that track what's being purchased where.

Educate your team on the golden rule: if they suspect misfuelling, do not start the engine. Even turning the ignition can activate fuel pumps and circulate contaminated fuel through expensive injection systems.

If misfuelling does occur, stay calm and call EEK Mechanical immediately on 0800 769 000. We operate 24/7 across New Zealand and will dispatch a tow truck to collect the vehicle and transport it to a certified workshop for proper fuel system drainage and inspection. Quick action minimises damage and gets your fleet back on the road faster.