Thread: Petrol v diesel economy

One of the main considerations for petrol vs diesel is how much the load factor changes on the vehicle. Petrol can be very economical especially with the modern systems that shut off at the lights etc etc, but as the load factor goes up petrol consumption cost increases in a frightening manner. Towing is one of the ways that you can seriously increase the load factor on a vehicle, especially when towing things that have a LOT of wind resistance (boats, box trailers). As soon as you factor in towing and a wide range of load factors, diesel seriously wins on consumption and that's due in no small part to the fact that petrol fuel tax is paid per litre of fuel whereas diesel is per KM meaning it doesn't get much more expensive if your diesel consumption goes up a litre or two per KM.

Diesel servicing is in some cases more expensive - but surprisingly enough some of the lightwieght petrols are by no means cheap come service time (as an aside, some EV's are quite a bit more expensive on service costs than people think - one owned by a neighbour is about 20% worse on tyre useage than the equivalent petrol model for example). People put a lot of concern into common rail diesel engines with fuel pump and injector costs, but some petrol engine designs are just as bad for repair costs. Mate just had to replace 6 individual coil packs and plugs on his wife's trundler, plugs at $55 each and coils at $325 a piece. And then it was a couple of hours of ripping bits off the engine to get to the bits needing replacement, replace a gasket set and some consumables and two hours to rebuild the thing. Total cost around $3500 just to replace spark plugs and coils...

A side factor, some petrol engines are highly allergic to water (a splash into the engine compartment can stop them cold) but some diesel 4wd's are now no better in this regard with the placement of critical sensors and electronics.