OIL ADDITIVES: To pour or not

Snake oil. Mouse milk. Whiffle dust. Take your pick — few products have earned such unflattering sobriquets as aftermarket motor-oil additives. And for the very good reason that these promised boosters of miles per gallon and extenders of engine life pretty much fail to live up to their often breathless advance billing.

Step right up and try 'em! Why not, a fleet manager might think, what with diesel through the roof and maintenance costs climbing, too? Even if there is no magic solution, it can't hurt to try, right?

The long and the short answers to those questions are the same: Think twice, long and hard, about using supplemental oil additives and demand proof of any claims being bandied about. Truck operators concerned with the high price of fuel and with how they can reduce engine maintenance and even extend engine life can't be faulted for considering all potential cost-saving avenues open to them.

Speaking to Fleet Owner, experts in the fields of original equipment (OE) additives, a key component of motor oil, engine lubrication and diesel engines, all discourage the use of aftermarket oil supplements, to put it mildly, but at the very least urge equipment managers to seek demonstrable proof of any claims via independent testing.

Indeed, even the CEO of an aftermarket firm that supplies a ceramic engine treatment product advises that third-party testing comes with the territory for anyone hoping to sell fleets additives of any type.

Following are perspectives on this topic from engineers with one of the industry's top OE lubricant additive suppliers, two engineers with major lubricant suppliers, an engineer with a leading diesel engine manufacturer, and the aforementioned aftermarket executive.

Taken together, their views suggest little has changed in the world of aftermarket oil additives except perhaps that these products can be — and increasingly are being — tested under such withering scrutiny that fleets can likely feel comfortable if successful results are realized.


For starters, says Gary Parsons, global OEM & industry liaison manager for OE additive producer Chevron Oronite Co. LLC, “keep in mind what is in motor oil to begin with: 75% of it is base oil and 25% is the additive package.”

Parsons points out Chevron Oronite's customers are lubricant manufacturers, noting “we sell to everyone” that makes motor oil for passenger cars and heavy-duty vehicles. He explains that OE additives enable motor oil to meet the various tests that must be met before it can receive its API donut and qualify for any supplemental certifications required by individual engine makers.

“To qualify an oil for the API CJ-4 service category alone,” he points out, “it must pass nine engine and six bench tests. The engine tests evaluate various aspects of performance, from piston deposits to valvetrain wear to foaming and aeration.”

Due to the sheer variety of these tests and the exacting standards of the requirements driving them, he says motor oil must be formulated with a wide range of additives.

“You can view additives as medicine,” suggests Parsons. “On their own [the original additives] are effective, but they can be harmful if you ‘overdose’ with them [by adding aftermarket additives] or use them in combination with [aftermarket additives], which can produce different results than those intended by the additive and lubricant engineers.

“Optimization of engine oil is an art,” he continues with a different metaphor. “The aftermarket additive can be a ‘good’ one, but you can still get into a dangerous situation by adding it.”

For example, he says to consider the “balancing act” between anti-wear and detergency performance in the oil. “The anti-wear additive that we put in oil today forms a protective layer as the metal surface heats up during friction. On the other hand, a detergent in the oil keeps metal surfaces clean. So putting in a supplemental additive that is a detergent will keep the engine clean, but it will cause it to wear out faster” by counteracting the anti-wear additive in the original oil.

According to Parsons, additive and lube manufacturers spend $1.5 million to qualify a motor oil formulation to required specifications. In short, he says that means everything that needs to be in the oil is already in there.

“We are not aware of any engine OEM that recommends aftermarket additives,” he points out. “And keep in mind aftermarket oil additive suppliers do not have the funds to qualify their products the way motor oil is. On top of that, they would have to test the additive in every different motor oil available” to make comparisons valid.

“The bottom line,” says Parsons, “is that motor oils are even more highly formulated today than ever and using supplemental additives can throw off the intricate chemical balances built into them. Look at it this way,” he adds, “if we could use a formula that would boost fuel economy say 5% or double the drain interval, wouldn't we put that in the oil in the first place?”


We spend millions on developing our motor oils and we don't recommend adding any supplemental additives to them,” Shell's Dan Arcy states flatly. “Since we do not test our oil with any supplemental additives, we can't speculate as to what adding them would do [to the oil]. On the other hand, with 20 million mi. of testing behind us, I can tell you how our motor oil will perform.”

Arcy says the problem with supplemental oil additives is two-fold: “At the most basic level, adding anything to the oil will dilute what is already in there — a carefully engineered additive package. And you can upset the chemical balance built into the oil. What can happen is the viscosity of the oil as well as the detergents, dispersants and antioxidants [in the original additive package] can be negatively impacted.”

Although Shell does not test supplemental additives as a matter of course, Arcy notes that one such product he studied “diluted the oil down by the exact same amount that was added,” which to his thinking means nothing was added, but what was there wound up diluted in strength.

“Putting that product in at, say a concentration of 10%, diluted our oil's anti-wear additives by 10%,” he reports. “The viscosity thickened up so much that the oil could no longer meet the low-temperature properties expected of a 15W40 oil. So using such additives can dilute or even change the chemical composition of the oil.”

Arcy says that he is unaware of any particular inquiries from the field about using supplemental oil additives, but he is seeing “definite interest in anything that promises to boost fuel economy.”

Mark Betner, heavy-duty lubricants manager for Citgo, says the oil supplier is getting questions from customers on whether supplemental oil additives work. He says several key arguments can be offered for not adding anything to motor oil.

“API CJ-4 oil certainly had to meet extremely strict chemical limits to ensure its compatibility with diesel particulate filters [DPFs] on today's engines,” Betner points out. “You can't put a blindfold on [and use supplements] without ending up violating what the industry did to create the CJ-4 service category in the first place.

“It is a chemical-limit issue,” he continues. “Aftermarket additives tend to increase sulfated ash, which had been brought down to a very low limit by the CJ-4 specs. We are troubled as a supplier that performed tests costing $1.5 million to meet the CJ-4 requirements. The simple truth is no one will run such a testing program [for supplemental additives] and with everyone's oil. So with [any claims] they are just guessing.”

Betner feels there “should be some harshness” expressed about the need for fleets to avoid oil additives. “Chemicals are very tricky things,” he says. “Think of it this way: If you go to the doctor and get a prescription and don't trust it and dump something else in with it, who can say what the result will be? Besides,” he adds, “if we thought there was something else that would work to save fuel or lengthen engine life, we'd put it in the oil ourselves.”

In that vein, it should be pointed out that while both Betner and Arcy argue against supplemental additives, they also agree that switching to lower-viscosity synthetic oil is a valid avenue to increasing fuel efficiency via lubrication.

“Many do have viscosity fear syndrome,” Betner says only half-jokingly. “But a fleet can save a million or more on their fuel bill [depending on power unit count] just by switching to a 5W40 synthetic. It's the lower viscosity that helps save fuel but at 5W40, it has to be a synthetic for it to be a high-performing oil.”


No matter what fuel efficiency claim is being made — and for whatever type of product — the trucking industry generally agrees that the gold standard for testing such claims is to run it through a TMC/SAE Type II controlled fuel-consumption test and see what the numbers say.

Offering no argument with that approach is Dean Rose, CEO of Southfield, MI-based CerMet Lab Co. The company manufactures and markets CerMet, which Rose says is a patented “nano-particle” ceramic conditioner formulated for cost-effective ceramic treatment of engines without requiring engine disassembly.

While he regards CerMet as an engine treatment — not an oil additive — he says it uses engine oil or other lubricants as a means of “delivery to the friction zone.” He says the product's fuel economy benefits last for about 60,000 mi.

Once the product is at work in the engine, it rebuilds worn metal surfaces and lowers the coefficient of friction, according to Rose. He says numerous tests in heavy trucks and power generators have demonstrated fuel savings of between 5 and 15% with CerMet.

That being said, however, he tells Fleet Owner that he knew truckers would want to see the results of a TMC/SAE Type II test. CerMet was put through those demanding paces by the independent testing firm of Claude Travis & Associates. The report issued by Travis verified the ability of CerMet to increase fuel economy in a freight-hauling Class 8 truck by 2.26%.

“We spend an awful lot of time on the oil-additive question,” admits Rose. “It's a two-edged sword. The nano technology we're using lets us apply a ceramic coating inside the engine without tearing it down. But even though we are using motor oil, or any lubricant, to deliver the product, we are hit by the same stigma. It's disastrous to be lumped in with oil modifiers.”

Rose says the product was not developed intentionally as a fuel-saver but to “restore and protect metal surfaces” to reduce friction and extend engine life. However, he says the rapid increase in fuel costs has made its impact on mpg another selling point.

“Trucking customers definitely ask to see the Type II test results every time,” says Rose, “and they ask to test the product themselves in their own trucks.”

No matter how additives are viewed, no one can argue fleets should not seek proof of any claim.


Add nothing but oil is the mantra of David McKenna, powertrain marketing manager for Mack Trucks Inc., who pulls no punches when it comes to offering an engine supplier's perspective on aftermarket oil additives. “No one sells good snake oil,” he remarks right off. “Look, you can't tell me that with all the oil companies spending tens of millions researching and developing lubricants that if something brewed up in someone's garage actually worked, they wouldn't all jump on it.

“We sell engines,” he continues, “and we do not want to see anyone adding anything to their oil or their fuel or coolant for that matter. What we want to see is the truck owner exercising vigilance over all three.”

McKenna is hearing more questions from customers about additives as the high cost of diesel is pressuring fleets to cut their fuel costs. Nonetheless, he urges fleets to take a holistic view of their engines.

He figures that all that has been done to vastly improve lubricant performance by the industry's latest oil spec (see “Positive Impact of API CJ-4” chart) should dissuade anyone from pouring in additives that offer no proof of their effectiveness.

“If someone is using the earlier CI-4 oil and chooses to put in an additive, they may end up increasing their maintenance costs to a level beyond what they would have spent to simply upgrade to CJ-4 oil,” he points out.

“The thing is, a remarkable job has been done to get oil to where it is today and it bears keeping in mind that modern oils are complex,” McKenna adds. “You do not want to do anything to upset the chemical balances engineered into lubes. On top of that, you need to consider how this stuff might impact emissions, including soot-loading, across the DPF.

“At the end of the day, you have to validate each and every thing you do,” he adds.

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