Shop Notes



Snake-oil salesmen have been around since the dawn of time. And today there’s no shortage of bottled products that promise a miracle cure for whatever ails your pickups.

There’s a big price difference between synthetic and conventional engine oils, but there’s also a big performance difference, too.

But there is one relatively new category of products we think warrants consideration by anybody who takes their truck maintenance seriously: synthetic engine oils. Synthetic engine oils, with prices for some topping $8 a quart, are more expensive to run than conventional mineral-based oil.

The question around the shop: “Are synthetics really worth the extra expense?”

The answer for most truck and fleet owners is going to be “yes.” To understand how much value they can bring, though, you need to know how they work, assess what it is you want to achieve by switching oils, and what needs to be done to accommodate vehicle maintenance plans around the synthetic’s strengths.


At the heart of every engine lube is a base oil, and without getting wrapped in technical jargon, there are mineral oil base oils and synthetic base oils. Mineral oils are created in a conventional refinery. The process produces oil molecules of different diameters—think bowling balls, softballs and baseballs.

For $12 to $15 a pop you can get a mail-in oil sample kit. The results can tell you how well your oil is holding up and give you early warning on things like fuel dilution, coolant in your oil, bearing wear and other engine problems.

Synthetic base oils are treated chemically so that the molecules come out the same diameter—all baseballs. The result is a thinner, more uniform film thickness and a base oil that offers better cold weather and load bearing properties. In many cases synthetics allow the use of a lower viscosity base oil yet give you comparable or improved wear protection. The thinner viscosities also reduce oil pumping losses in the engine, which improves engine efficiency and ultimately fuel economy.


What’s less standardized about oils are the additives mixed in with the base stock. Much like the keepers of award-winning barbeque rubs and sauces, the exact compositions of these additives are closely guarded trade secrets. (See “Engine Oil Secrets”— But they all strive to achieve the same results regardless of the additive package—improving the performance of the base oil stocks.

Truck manufacturers mandate a specific viscosity and oil change interval regardless of whether you use synthetics or not.

“An engine oil additive system will include a detergent to keep components clean and a dispersant to insure that the soot particles produced during combustion are dispersed within the lubricant and don’t form clumps or sludge,” says Peter Thomson, director of C&I marketing, Valvoline International.

“The package will also contain anti-oxidants to prevent the base oil from being oxidized and made thicker, and a viscosity modifier, which is a heat-sensitive component so as the oil heats up it maintains a level of thickness within the lubricant. It may also contain a pour-point depressant, which allows the oil to flow at very cold temperatures, and other chemicals, as necessary, to improve the lubricant for the intended market,” Thomson says.


In highway applications, owners of Class 7 and 8 fleets have reported fuel economy gains of 2 to 5 percent using synthetics. That’s a big deal for the big rigs, and still significant for pickup truck owners.

Even if you only get a 3 percent improvement on a truck getting 15 mpg, the savings adds up to about $30 per 5,000 miles based on fuel costing $3/gallon. That’s more than enough to pay for the extra cost of even the most expensive synthetic oil.

Does that mean that synthetics are just a break-even proposition? Not really. Many engines today run hotter than previous models and the premium additive packages that come with many synthetic oils improve their oxidation resistance thus protecting your engine against heat longer. And the low viscosity formulations, in addition to reducing pumping pressure, offer cold weather advantages. Manufacturers will tell you that the first three seconds after start up in sub-freezing temperatures can do more damage than any other moments in an engine’s life.


Big rig and heavy equipment fleets have been extending oil drain intervals for years. So why don’t automotive OEMs cut pickup owners some slack? Why do most say you void the truck’s engine warranty if you exceed the factory drain interval?

Because the guys who buy lube oil by the barrel extend their drain intervals only after establishing a oil-analysis program and working hand-in-hand with their equipment dealer and lube supplier.

The automotive manufacturers set their parameters based on a worst-case scenario and they know that not every pickup owner is going to pay that much attention to oil changes and oil analysis.

The OEM maintenance limits are conservative, but not without good reason. Synthetic or not, the owner’s manuals are very specific about oil/filter change intervals. Pay heed to their guidelines.


You may find synthetic oils are great for your trucks once you start compiling data – or you may find the cost-value proposition less compelling.

“Just because you have synthetic-base oils in a formulation, that does not guarantee the product is going to be the optimum product for that application,” says Lilo Hurtado, commercial vehicle lubricant application engineer for Exxon-Mobil.

“You still have to be sure the entire formulation is going to give you the performance you need to protect that equipment or that engine,” Hurtado continues. “We don’t say that one size fits all. We customize our additive systems for our synthetics as well as some of our premium engine oils.”

And maintenance costs drive a lot of decisions with heavy trucks and equipment. Highway haul trucks have oil sumps with 12- to 15-quart capacities. Pickups with gas engines typically have 6- to 7-quart oil capacities, while their diesel brethren run double that amount.

While economic factors drive extended-drain intervals on big rigs, that’s not the usual thinking for heavy-duty pickups. But it might be worth considering.

Even if it’s not, the added benefits synthetics bring to the table (great engine protection and a little boost to fuel economy) make them attractive.

Web Extra

If you do want to extend the oil-drain intervals in your pickup, check out “Extending Service Intervals” under the tech/maintenance section of