Bottom Line
Maintenance Q&A

Paul Abelson
technical editor

Last month, we addressed your questions about fuel additives. This month, we’ll tackle the second part of the additives question, oil additives. These questions come from OOIDA board member Joe Rajkovacz.

“Fuel and oil additives — 
are they any good? 
Are they a waste of money? 
Do they extend the life of the engine? Are they cost effective? 
Is one any better than the other?”

Great questions, Joe, but the answers are complex and controversial. For instance, there’s currently a running debate in the OOIDA Members-Only Forums on the Internet. In the “Truck Maintenance and Repair Forum,” two members whose opinions I value highly seem to be on opposite sides, each with his own reasons. Ron Fulton has a number of posts to the effect that oil additives should not be used. James Spangler, on the other hand, has done some testing with one of the most popular additives among OOIDA members, Lucas. He loves the product and feels his tests have demonstrated its value.

What do the oil companies say? 
To find out, I researched professional journals on lubrication and spoke with my contacts at The Technology and Maintenance Council (TMC) from the oil companies, engine manufacturers and wholesale oil additive chemical suppliers, companies like Lubrizol and Exxon-Mobil. They sell the component chemicals that oil refiners put into their oils.

They were unanimous in their opinions: Truck operators should not put anything in their oil. Oil is a delicate balance of about 30 percent to 35 percent additives blended under controlled conditions and proprietary processes with selected base stocks of mineral or synthetic oil. Having too much of any particular additive could reduce the benefits of other additives, and if an aftermarket additive is not compatible with a component or refiner’s oil, the additive could damage the engine.

Engine oils are formulated to meet a series of standards created by an industry committee of engine and lubrication engineers, under the auspices of the American Petroleum Institute (API) and the American Society for Testing and Materials (ASTM). The committee, which developed CI-4 oil for EGR engines and all the previous grades since CC, is chaired by SAE Fellow and active TMC member Jim McGeehan of ChevronTexaco.

Any oil must pass each and every test (now up to 14) to qualify for the designation of the API symbol on the container. In addition, engine companies may require additional testing for use in their specific models. Not including development costs, testing alone costs hundreds of thousands of dollars, because each test requires that engines be run for specified periods of time or miles. Oil, the experts say, is a delicate balance of chemical and physical properties that can easily be upset.

What do the additive suppliers say?
I’ve spoken with many oil additive, supplement, conditioner and fortifier makers at trade shows around the country. Most have the same stories.

Typical comments are: “The oil companies don’t want our products used because it would cut their sales volume by at least 10 to 20 percent (mix ratios) and probably more because we make oil last longer,” and “We have a breakthrough product, and the establishment testing hasn’t caught up with our performance.”

Many rely on anecdotal evidence, not controlled tests. Some refer to “a prestigious university” or “a well-known testing laboratory,” but rarely identify which ones. Many that are identified are outside the United States. I still haven’t seen evidence from any manufacturer with properly documented tests.

Normally, when test results are published, verifiable reports give the location and dates of testing, names of personnel conducting the tests, a description of test procedures if new, or a list of established test protocols developed through the scientific process (reaching consensus and addressing all objections) by ASTM, SAE, API and other recognized technical organizations.

How can you tell if an additive is effective?
The problem is, you can’t, unless you have the equipment to run two identical engines on a dynamometer under identical loads for a million miles or more under controlled conditions in a climate chamber. Then you have to tear down, inspect and reassemble both engines periodically. And the oil companies who say they have tested additives (in hopes of gaining exclusive rights so they could get a competitive advantage) have not been able to discover any advantages.

Today, it is not at all unusual for owner-operators to get more than a million miles without ever having the oil pan or cylinder heads off. How do you measure what an additive does for you, especially without a control engine to compare with?

Even if you set specific goals for your additive, such as increasing fuel mileage 1/2 mpg or extending oil drain to 30,000 or 40,000 miles, without a control, how do you know what fuel economy or oil life you would have gotten without an additive?

The Federal Trade Commission has cracked down on oil additive manufacturers in recent years for false and misleading advertising claims. Many of the most popular brands have received sanctions.

Is there an exception among additive suppliers? 
I don’t know, but because so many OOIDA members are convinced the additive they use has helped with no detrimental side effects, I contacted the one company most often mentioned in my research, Lucas Oil.

This is a well-established company, as demonstrated by the fact that as I write this, the NHRA Lucas Oil Nationals are being held at the Route 66 Drag Strip in nearby Joliet, IL.

Bob Patison of Lucas described their oil conditioner as part of a full line of oil products, including mineral, semi-synthetic and full synthetic oils and other petrochemicals. They are the only additive manufacturer I know that has a full line of oils, too. Bob mentioned that while it is impossible to test for compatibility with every single oil on the market, Lucas does test with all the popular brands from major refiners.

Lucas has no chlorinated paraffins, PTFEs, nor molybdenum compounds. He would not tell me what goes into Lucas’ additive, but he said the product uses compounds other than zinc. It is designed to provide greater film strength, improve heat resistance and deter the effects of fuel dilution.

Can we reach a conclusion?
This is one of those questions drivers argue about now and will argue about for decades to come. I’ve heard owner-operators swear by the oil they use, most often Rotella-T, Delo 400, Delvac 1300 or Delvac 1. I then hear those same drivers rave about the good that Lucas or some other additive does.

Well, which is it? Is the oil good, but only with the additive? And what does “good” mean? How is oil performance really determined? Engines and oils have improved in the past decade, and we have 10-year-old engines that have gone a million miles or more with extended oil-drain intervals.

My own personal opinion is that if it were my truck, I’d pick one oil based on its reputation and use it for the life of the engine without any oil additives. One of the oils I’d consider would be Lucas. LL Paul Abelson can be reached at

What does oil do?
Everyone knows that oil lubricates the engine. It is pumped under pressure to form a slippery film between moving parts so the parts slide or mesh together easily. But oil has many more functions. According to the American Petroleum Institute (API), engine oil:

  • cleans the inside of the engine;
  • seals against combustion blow-by;
  • helps cool the engine;
  • protects from rust, corrosion and oxidation; and
  • protects from wear caused by friction.

What do additives do?
Oil additives claim to do many things, usually according to the type of additive chemicals they contain.

l Additives containing viscosity improvers claim to improve an oil’s resistance to thermal breakdown.

l Friction modifiers are used to increase fuel mileage.

l Those with detergent and suspension agents, usually zinc compounds, increase Total Base Number (TBN), a measure of oil degradation and acid-fighting properties.

l Additives with solvents and/or detergents claim to keep internal engine parts cleaner.

l Additives with solids, such as DuPont’s Teflon and other PTFE compounds or with molybdenum sulfide, claim to increase fuel mileage by reducing friction.

Caution: The use of additives with solids may result in clogged bypass filters, rendering them ineffective. They have also been shown to block oil galleries, reducing lubrication and causing added wear and catastrophic failures.