Truck Topics

Expediting Vans: Gas or Diesel Engines?

By Bob Thomason
Posted Oct 14th 2002 11:26AM

During my many years in expediting, I used to get into friendly discussions with some of the other cargo van operators at the truck stops about the qualities of diesel engines versus gasoline. It seemed like everyone had an opinion about either one, and pretty strong opinions in some cases.

The diesel guys were usually the most vocal and adamant about the benefits of their type of power plant; there was no question about it, diesels were the only choice for the truly professional driver.

They had a variety of reasons for their engine preferences and they would expound long and loudly about why no one in their right mind would run a commercial van over the road with a gas engine.

In my expediting career, I ran gas engines only and was happy with the cost, performance and longevity of thatkind of power plant. Sometimes, mostly against my better judgment, I would be drawn into these parking lot discussions.

Looking back, it seems like I was the only defender of the gasoline-burner, so I had to get my facts together when on the minority side of the debate.

I'm not a scientist or economist, so I could only talkin layman's terms about the virtues or deficiencies about each engine. The talking points that the diesel lovers invariably brought to the discussion are listed below along with my response.

1. "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, idle for long periods of time, especially in cold weather when the truck heater can mean the difference between comfort or a really cold night.

I was always concerned about keeping the main battery charged in the frigid temps, so that was another reason. In one particular stretch of below zero days, I left the van running for three days straight.

I used to idle my gas engine on the hottest days for the air conditioning, but I will confess I was always keeping an eye on the temp guage. (It never did overheat)

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 went OTR in expediting, I did consult with some mechanics before I subjected the van to extended idling and, to a man, they told me don't worry about it.

2. "Most of the time I can buy diesel fuel cheaper than you can buy gas."

A short while back that was true.

I remember times when diesel would be $.10-$.20 per gallon cheaper than the gas I was buying, but it would seem that diesel has found it's way into the sameprice neighborhood as gas.

And it wasn't that long ago when the diesel prices were substantially higher than gas, and I recollect the big truck drivers screaming about that. As I write this, the price at the truck stop down the street has diesel at $1.52 and gas priced at $1.45.

3. "After all, that's what they run in the big trucks, and they get millions of miles out of them, right?"

Yes, in the Class 8 type trucks, they figure on getting LOTS of miles from their investment. I think I read somewhere not long ago that with today'stechnology, the big truck motors initial major overhauls now come at about a million miles or so. Of course,that kind of durability comes at a price, that of a Class 8-sized vehicle, which is just a little more than a cargo van.

Besides the price, the comparison of diesel-engine cargo vans in expediting to the mega-miles that the big trucks run doesn't really work. Most of the expediting companies only allow (to my knowledge) a service life of 5 or 6 model years. In my case, I ran as a solo driver in my years in expediting, averaging between 95k-105k miles per year in that time.

Most of the cargo van owner/operators who I knew usually put anywhere between 300k and 500k on their vans before trading-in, both diesel and gas. It would seem that with the service life restrictions imposed by the companies, any extra longevity that the diesel engines enjoy will never be used by the original owner.

In my particular case, which I admit is a little unusual, I ran a 1992 GMC 3500 with a 350 gas engine for three different companies over a timespan of seven years. When I retired that van, it had 689,000 miles on the original engine with, thankfully, no major maintenance done on it. In fact, we never even pulled the valve covers.

I'm not bragging about that motor, I didn't do anything special, just regular oil changes and tune-ups. I'm as surprised about the mega-miles I got out of that investment as the people I've told about it.

Since retiring that van, I've talked to other expediting van drivers and have heard similar stories about their gas engines and how they've gotten 500k, 600k and even more out of their motors.

The point of all this is that it's not all that unusual for gas-burners to get mileage totals that used to be theprovince of only diesel motors.

4. "I like the low-end torque I get from a diesel, that means pulling power."

I never had the opportunity to drive a "heavily" loaded diesel-engine van any distance through hilly or mountainous areas, so I can only state that if my 350 c.i. gas engine was deficient in power, I never missed it. I had loads of 3,000 to 4,000 lbs in thevan on occasion, and never noticed a lack of pulling power except on the steepest of grades.

So, instead of maintaining 65 mph up those long hills, I was content to let it drop down to 55 mph.

5. "I know a guy who's getting 21 mpg with his Ford Power Stroke!"

That's pretty good mileage for a full size van and I've heard of other diesel owners getting even better mileage than that.

In my case, I'll admit that my 350 never got much better fuel mileage than the high 17's. In talking to other gas engine owners, I found that my mileage was about average in comparison with theirs. In breaking down the fuel cost alone, I've used the equation of 1 year=100,000 miles. With an average fuel price of $1.50/gallonfor both diesel and gas, it works out to:

Gas Engine - $8,823.00

Diesel Engine - $7,142.00

This gives us a difference in $1681.00 in fuel savings per year in favor of the diesel.

Not bad.

Most of the figures I've gotten from dealers and the van o/o's I've talked to indicate that the diesel motor will usually cost $4,000 more than the gas engine. And that cost has to be financed upfront.

With that figure in mind, the diesel motor should pay for itself within 2.40 years of purchase through fuel savingsalone.

Again, not bad.

If an owner/operator were to judge the merits of dieselvs gas on the fuel savings alone, it's an obvious choice-the diesel wins that one.

However, there are some other factors that we haven't mentioned which should be considered:

Repair costs: Over the years, I would occasionally check with different mechanics about the relative costs of diesel vs. gas repairs. The figures I got from them showed a repair/rebuilding cost of anywhere from one-third to one-half less for a gas-burner compared to the diesel.

Availability of diesel mechanics for those who live in smaller towns or rural areas might sometimes pose a problem for those diesel van owners. You can't always take it down to the corner garage, and this might force a trip to the dealer with their usually higher repair prices.

For the owner/operator who also does his own mechanical work, the diesel poses it's own set of problems; it's tough to get diesel-specific part sat the local AutoZone, so once again, it's back to the dealer.

The noise: For myself, I've heard some of the motors in these vans that easily rival the sound level of Class 8 motors and it seems like those are always the ones that pull into the parking slot next to me around 3 am.

I guess one gets used to the noise and clatter of a diesel, but there have been many times that, when trying to hold a conversation with a driver in a van with an idling motor, I've just had to cut the talk short because I couldn't hear.

The smell: Maybe the odor of diesel fuel is an acquired taste, but sometimes that sickly sweet smell really gets to me and I know it must effect a number of other drivers too.

The oily soot emanating from the tailpipe that coats the lower quarter panel on many vans I've seen is also something I can do without.

Cold weather problems: I remember during the winter of 1994, I was dispatched on a number of runs that I would take off of a diesel van driver whose truck would not start, either due to fuel gelling or some other reason.

I have to admit that I haven't kept up with the additives that are currently used, so I don't know if this is still the problem it was just a few years ago. I do know that the fuel problems they experienced back then cost a lot of drivers substantial dollars.

Well, them's my thoughts on the subject. I don't claim to be scientific about this, just a couple of figures mixed in with my experiences and those of others that lead me to prefer the gas-burners over the diesels.

I'm sure some of those diesel-owners out there have some things to say in defense of their engine choice and I'd like to hear 'em.

Thanks for reading and to this web sitefor letting me spout off.