“So, which do you think is better, Oom, diesel or petrol?”

This from my oldest sister’s youngest, whose courier business in the Northern Cape has grown to where it now needs a second vehicle.

“It depends how heavy your parcels are, how far you drive and how much of it is on sand.”

“Oh, the loads weigh about 350kg and my longest leg from Upington is some 250km to Marydale and Kenhardt, most of it on tar.”

“Then it’s easy,” I told her. “Get a hatchback or van with good ground clearance, the latest variable valve petrol engine and a full-size spare. Any of the imports from India will do.”

“But everyone says I’ll get more mileage out of a diesel, and it will climb hills easily because it’s stronger,” she said.

The heavy stuff

“Nig,” I said, “for your needs, a diesel is like using a combine harvester to mow the lawn. True, diesels are stronger and go further on each litre of fuel, but they also cost on average 15% more to buy than petrol, can cost ten times more to fix and what they don’t tell you, is that the injectors on modern diesels cannot handle dirty diesel.

“Why, just yesterday Stefan’s dad, you remember him, the young farm manager from Ohrigstad? Anyways, his dad was telling me he got watery diesel in his bakkie while on a dive trip in Inhambane, and he had to tow it back. That diesel destroyed the expensive injectors and pump. 

“Now, if he drove a petrol bakkie, he could have solved his problem with a bottle of rubbing alcohol and a new filter. And don’t even get me started on diesel particulate filters. Those things are supposed to burn diesel soot, but they only do so when you drive in top gear at highway speeds for at least half an hour. For people who rarely leave town, they just clog up. 

“Then there is the lack of price controls on diesel. I tell you, Nig, it is highway robbery at any franchised fuel station. So, most of us who drive big diesels try to save by filling up at a truck stop, but then you worry about the diesel quality. And unless you add urea and use a particulate filter to trap and burn the soot, you are spewing out cancer clouds as far as you drive. 

“No, Nig, the only scenario where a diesel engine will benefit your courier business, is when you move very heavy payloads over long distances. But you will not be doing the climate or our lungs any favours while at it.”

Keep it low and slow

“Okaayyyy Oom, no need to speak so loud! You convinced me. A petrol hatchback it is. At least until I can afford a vertical lift-off blimp. But what was that about driving on sand roads?”

“Huh? Never mind sand for now. What’s this about a blimp?” I asked.

“Aha, there’s something my clever Oom Schalk doesn’t know about! Oom must check it out. Helium-filled blimps to carry cargo or tourists on slow sky cruises. I really, really want to pilot one. It is transport’s future.”

“Helium blimps you say? That is a scarce gas, but I guess you won’t be burning it as fuel, instead storing it in the balloon. I’ll be checking it out for sure. But to answer your question on sand, the first rule of 4×4 driving is to keep it low and slow, which is where diesels work best.

“You can crawl over rocks or dunes without having to worry about keeping your momentum in the right direction. Yet low and slow won’t push you through sand or mud, where a front-wheel-drive petrol engine will pull you through. 

“Your mom proved this every summer when my bakkie bogged down and she would just rev past on her way to school. Give her my love and call before you buy. I have to go milk Trixi.”