Should you buy a diesel truck

Should I Buy A Diesel or Gas Truck?

If you are looking for a heavy duty truck, the type you choose usually comes down to personal preference. Ford, Chevy and Ram all make some great trucks that will get the job done. The big question that many find themselves asking is whether or not to shell out the big bucks for a diesel engine. Let’s take a look at whether you should or should not get a diesel.

If you need the power of a diesel engine, it is a no brainer, get it. The engines are designed to work hard and pull some massive amount of weight. If you have a legitimate use for a diesel, this article is not for you. This article is for those who just “want a diesel”. You might tow occasionally or you might not even tow at all. The cost of a diesel is a hard one to stomach for a want. Checking off that option will, after all, add over 9000 dollars to the cost of your truck. Let’s see how much this option really costs though.

Trade In Value Difference

It is hard to say what the exact value of your 2019 heavy duty will be four years from now, but we can take a look at the past to get a pretty good idea. To gauge the overall cost of a diesel, we are going to look at the life of a 2014 Ram 2500 4 door Tradesman. One with the 5.7 Hemi engine and one with the 6.7 Cummins Diesel engine. Both will have 80,000 miles on them and will be traded in to the dealer in 2019.

The trucks are similarly equipped with the only difference being the addition of the $8160 Cummins engine. The Ram with the 5.7 Hemi has an average trade in value of $19563 according to Kelly Blue Book. The Ram with the Cummins has a trade in value of $25991. That is a difference of $6428.

Fuel Economy Difference

Now, let’s look at the cost of fuel. Diesel engines are far more efficient than gas engines and for the sake of this article, we are going to assume that the diesel achieves 18 miles per gallon while the Hemi achieves 14 miles per gallon. This assumes absolutely no towing but if towing were considered, it is expected that the fuel economy difference of the diesel would be even greater.

In 80,000 miles, the Hemi would use 5714 gallons at an average cost of $2 a gallon which would be $11428. The Cummins would use 4444 gallons at an average cost of $2.40 a gallon which would be $10665. That is a fuel savings of $763 for the diesel engine.

Maintenance Difference

These are identical trucks so the only difference in maintenance will be in oil changes and fuel filters. Assuming you can do your own oil and filter changes, here is what you should expect.

Oil Changes

The oil change interval on the Hemi will be every 8,000 miles so you can expect to perform 10 oil changes on the vehicle. 7 quarts of oil (at $5 a quart) and a $10 filter equals $45 for an average oil change. Your cost may vary a bit but $45 a change is a reasonable average. That makes the total cost of oil changes $450.

The Cummins will need an oil change every 10,000 miles so you can expect to performa 8 oil changes. 12 quarts of oil (at $7 a quart) will be needed as well as a $10 oil filter. That makes the cost $94 for an oil change for a total of $752.

That is an additional cost of $302 for the diesel.


The Hemi will require a fuel filter change every 30,000 miles so you will do two of these. At a cost of $30 each, that will total $60.

The Cummins will require two fuel filters to be changed every 15,000 miles. This means you will perform five of these changes at $100 a pop for both filters. That is a cost of $500 for fuel filters. In addition, there will be a Crankcase Venitlation Filter that will need to be changed around the 65,000 mile mark at a cost of $80. That brings the total filter cost to $580.

Other filters like transmission and air filters will have similar cost and life expectancy so we will not consider the cost. This makes the extra cost of diesel filters $520, assuming that you can do the work yourself.

Total Cost

Now, let’s bring it all together to get the total cost of diesel ownership on a 2104 Ram 2500. The cost to acquire the diesel is $8160 minus the added trade in value of $6428, that makes the cost $1732 at this point. Now, add in the fuel savings of $763 which will make the cost of ownership $969. Finally, lets subtract the added cost of maintenance which is $302 in oil changes and $520 in fuel filters and a crankcase filter. That brings the cost of ownership to $1791.

When you work it all out, the cost of the diesel is not nearly as intimidating as it seems. Is the cost of $1791 worth it to own a diesel? That is a decision that you need to make.

Of course, there is one more thing to consider before you make your decision. That is the REAL cost to acquire a diesel. Sure the invoice price was $8160 in this case but that is likely not the price that you would have paid. Like everything else at the dealer, there is a big markup and diesel equipped trucks are often discounted much more than their gas counterparts. So, chances are good that that diesel engine might have only cost an additional $7000 back in 2014. That brings the real cost of ownership down into the hundreds of dollars.


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James Car is a finance, loan and budget expert based in the United States. After attending Brookhaven college, he went on to become a successful entrepreneur. He now enjoys writing articles that help people save and make the most of their money.