Cargo Van Power: Gas or Diesel?
For the expediter who is spec'ing his new Class 6-8 truck, the engine choice usually comes down to what make of engine (if different OEM's are available) and what horsepower rating he's after. For many years, the diesel engine has been the standard power plant in straight trucks and tractors, but for the cargo van owner-operator, the choice is gas or diesel.
The question of which type of engine provides the best performance, economy and longevity remains and the cargo van manufacturers (GM and Ford) keep the issue alive by offering both gas and diesel options. That is, except for the Dodge Ram van's replacement , the Sprinter, which has only offered the Mercedes five-cylinder diesel since its inception.
Not long ago, Contributing Writer Bob Thomason wrote of the gas vs. diesel controversy. Thomason answered the diesel proponents' arguments from an admitted gas engine fan's perspective, but he did touch upon some salient points:
Diesel Fan - "I like the low-end torque I get from a diesel, that means pulling power."
Thomason - Typically, gas engines make more horsepower, while diesels produce more torque. By design, gas engines rev up faster and are able to reach higher rpm peaks than diesels. This allows them to attain higher horsepower numbers and quicker 0 to 60 mph times. The torque advantage diesels have is perfectly suited for pulling heavy loads up steep grades.
Personally, if my 5.7L gas engine was deficient in pulling power, I never missed it. I had loads of 3,000 lbs. in the van on occasion, and it seemed as though I had adequate power except on the very steepest of grades.
Dieselman - "They put only diesels in the big trucks, and they get hundreds of thousand of miles out of them, right?"
Thomason - Yes, in the Class 8 trucks, they figure on getting LOTS of miles from their investment. Of course, that kind of durability comes at a price, that of a Class 8-sized vehicle, which is just a little more than the price of a cargo van.
Many of the expedited carriers only allow a service life of 5 or 6 model years. With those restrictions, any extra longevity that the diesel engines offer will never be used by the original owner.
Anyway, it's not unusual for today's gas-engined cargo van to rack up 300k - 500k miles during its life span. In the case of one expediter I knew, he retired his GMC gas-engined van with 697,000 miles on the clock and never even pulled the valve covers. (He was leased to a small carrier with a very liberal policy regarding the age of vehicles.)
Diesel Fan - "I know a guy who's getting 21 mpg with his Ford Power Stroke!"
Thomason - That's pretty good mileage for a full size van and I'm aware of other diesel owners getting even better mileage figures, particularly with the Dodge Sprinter (22-25 mpg).
Diesel fuel has a higher energy density than gasoline. This means that it takes more gasoline to equal the power output of diesel, making diesel engines more efficient per gallon of fuel burned.
Also, because diesel engines use the more efficient direct fuel injection method (fuel injected directly into cylinder) compared to the port fuel injection setup used in gas engines , the diesel system leaves very little unburned fuel. Diesels also use about 1/3 as much fuel at idle as gasoline units.
Because diesel fuel is easier to refine, at one time it was typically cheaper than gasoline. However, those days may be gone for good. We've all seen the frightening rise in diesel prices over the past many months and the per gallon price advantage that diesel enjoyed may be just a memory.
With Ultra Low Sulfur Diesel fuel scheduled to hit the market in mid-'06, availability could be problem along with rumored lower fuel mileage and higher fuel prices.
Diesel Fan - "You can't idle that gas engine like my diesel."
Actually, with today's computer controlled fuel injection gas engines, you CAN idle like a diesel. That is, you can idle for long periods of time, especially in cold weather when the truck heater can mean the difference between comfort or a very cold night.
It seems that back in the days when carburetion was the standard technology, gas engines would experience problems after long idle times, but with the modern fuel systems, those problems are eliminated. When I first entered expediting, I consulted with mechanics before I subjected the van to extended idling and they told me that it wouldn't be a matter for concern.
Thomason's pointsBecause diesels are heavier-built, a diesel engine can weigh several hundred pounds more than a comparable gas model. This can result in increased wear on front end components, tires, etc.The purchase price difference between, let's say, a Ford 5.4L V-8 gas engine and a 6.0L turbo diesel V-8 will be a few thousand dollars. Regular maintenance on a diesel is more costly than its gas counterpart due to the larger volume of oil required by diesels along with fuel filters and water
separators that need to be serviced more often. Modern gas engines have another advantage due to extended service intervals on things such as spark plugs, engine oil and antifreeze. Diesels are still noisier and vibrate more than gas engines. At idle, the rattle, clatter and shake of the diesel is clearly noticeable as anyone who has been parked between two idling diesel vans can attest. Odor - Need we say more? Cold Weather - Starting and fuel gelling
Cargo van expediters weigh in on gas vs. diesel
I've used gas vans for years and if you maintain them, they will do just fine. I get 15 mpg. I drive a 2004 Ford E-350 one ton, gas engine (and get) 15.5 to 16.5 mpg, it depends on how fast I drive.
Use the (cost difference between gas and diesel engines) for your expediting start up costs.
Terry O'Connell has been a cargo van expediter since 1989 and has owned both gas and diesel-engined vans. We'll let him tell the story:
"My first two vans in this business were GM vans with the International diesel and EO4D transmission. In both cases, the purchase price on those engines (at that time) was around $3,500-$4,000 greater than a gas engine."
"I was happy with the mileage from the diesels, but the repair costs of both of my diesels exceeded my expectations. I had problems with the transmissions and the accompanying downtime - about a week in each instance."
"Another issue was the availability of diesel mechanics to work on my vans. There's no shortage of people to work on the gas engines, but sometimes I had extra downtime until a diesel mechanic had some time to work on my vehicle."
Terry continues, "All of the mechanics I talked to agreed that the EO4D transmission wasn't suitable for the International engines and the higher torque they produced."
"I think that whether a driver buys gas or diesel, he's going to find a way to justify his decision. All of the vans - Ford, GM or Sprinter - are going to carry the same kind of weight. What it's going to come down to is the mileage and durability of the vehicle."
Terry also touches on another aspect of the gas vs. diesel question:
"I'm getting the fuel surcharge that's based on diesel prices at 10 mpg, but I'm operating a gas engine in a van that's getting 15 mpg."
"My Chevy 3500 van has 538,000 miles on it and still runs great while getting 15 mpg. I've idled all night without problems and have stayed quite warm. My next van will definitely have a gas engine."