6

Our landscaping company is going to purchase a new medium duty truck. We have diesels and had just defaulted into looking for another diesel powered truck. However the mechanic we use (and trust) said that we should consider gas engines for a number of reasons:

  1. Initial cost for gas engine is lower
  2. Mileage is similar/diesel oil is more expensive than gas
  3. Gas engines more suited for the short-trip (2 - 10 mile) type driving we do. We might put 15k per year on a vehicle, but typically quite a bit less.
  4. Long term maintenance on gas engines is cheaper

We can evaluate the first three claims ourselves, but we have no idea about comparing the long term costs of maintaining the engines.

  • 1
    Can you be more specific about which particular truck you're considering? Also, you should consider the torque vs. power trade-offs. – Bob Cross Oct 16 '14 at 21:13
  • I was trying to avoid favorite truck discussions. However We just learned that the gas version of the truck weve been looking at has a payloaf capacity that is half of that of the diesel based on gross vehicle weight. – That Idiot Oct 17 '14 at 0:53
  • @ThatIdiot Did you ever resolve this? If so, could you post an answer to your question? Happy New Year and thanks for contributing. Sorry we couldn't give you an answer. – DucatiKiller Jan 5 '16 at 6:17
  • 1
    @DucatiKiller - if you're killin Ducs, you must ride an Aprilia ;-) - But to answer your question, no, we never really resolved the question. However we wound up purchasing a diesel truck for the towing/payload benefits and because our informal survey told us that the model we purchased was practically industry standard around here. – That Idiot Jan 5 '16 at 12:32
  • You are a smart man. Yes, I ride Aprilia's. I don't like to brag about my ability to kill ducs and how amazing the Aprilia does it. I also don't like to talk about how much better the Aprilia is than a dead duc. It's just how I am. :-) – DucatiKiller Apr 9 '16 at 20:51
2

Diesel engines can these days have for example these kinds of problems:

  • The turbocharger can break. Gas engines due to the high RPM they are capable of running at don't need turbos, but a turbocharger is practically mandatory in a diesel engine to obtain any useful amount of power.
  • Direct injectors can fail. Replacing them is extremely expensive. I once read an article about the repair business of these injectors. Many countries have special facilities with cleanrooms to repair these injectors, because repairing, although expensive, is less expensive than replacing.
  • The particulate filter can fail. It is a very expensive component to replace.
  • The exhaust gas recirculation system that is mandatory to combat NOx can clog the intake valves. In (non-direct-injected) gasoline engines, the injection of gasoline into the valves will naturally keep the valves clean, whereas in a diesel engine there is no such mechanism.

So, it's not the regular maintenance that will cost more, it's the extremely expensive parts that can fail. Note that some gasoline engines have turbos, and gasoline direct injection engines have direct injectors and also may have a particulate filter. The intake valve clogging problem also applies to gasoline direct injection engines except some engines that have both indirect and direct injection systems in parallel (e.g. some DI engines by Toyota).

When taking into account the NOx emission issues as well that have led many large cities to imposing diesel bans, I would say gasoline is the clear winner for the long run.

Consider also this: if you fill a modern gasoline car with diesel, no long-lasting damage is done. Just empty the tank and fill again with gas and you're good to go. However, if you accidentally fill a modern diesel car with gasoline and actually start up the car, the repairs will cost thousands.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.