Out of the frying pan …

One friction modifier whose efficacy is the center of much attention is polytetrafluoroethylene (PTFE or TFE, for short, the generic name for DuPont Chemical's Teflon), of which there is a family of similar yet distinct formulations. PTFEs boast the lowest coefficient of friction of any known material. Back in 1980, DuPont told everybody that their studies showed PTFE offered "no significant benefits as an engine additive." This statement set off a storm of controversy that still has DuPont spokespeople walking on eggs. However, you will notice that none of the PTFE additive suppliers are allowed to use the word "Teflon" in their advertisements or product information.

For most people "Teflon" calls up the mental image of a no-stick frying pan. PTFE engine oil treatments work quite a bit differently than the PTFE in a cooking utensil, however. When coating a frying pan the metal is spotlessly cleaned in prepara tion for the application of PTFE. This situation is never going to happen spontaneously in a motor, no matter what you use as a pour-in cleaning agent.

As a motor oil additive, PTFE powder is held in suspension in a liquid carrier. Because most (if not all) PTFE resins are more or less tailored for their end use, and because few (if any) of the available powders have been tailored for use as an oil additive, PTFE oil additive marketers must select a PTFE that was compounded for some other purpose (such as frying pans, wire insulation, etc.).

Powders come in different particle sizes, with the smaller sizes typically costing a bit more than the larger sizes. For those who can not afford (or find a source for) the size they want, custom grinding houses can take a less expensive 400 to 500 micron powder, freeze it with liquid nitrogen, and grind it to whatever size is needed. Most of the PTFE oil additives use a particle anywhere from 20 microns down to the sub-micron size.

The very characteristic of PTFE that makes it so slippery also makes it tough to get it where the action is in the motor. For this reason, the carrier liquid is often an affinity agent that bonds the PTFE to the friction areas. These take the form of chemicals such as tricresyl phosphate (TCP) and triaryo phosphate (TAP). The use of the right affinity agent has the positive side effect of boosting lubrication performance whether or not there is any PTFE involved. Some of the affinity agents are so tenacious that it is jokingly said you could lubricate your engine with water if it had enough affinity agent in it. Because of this, some high-performance oils (such as Synthoil) are blended to include affinity agents from the start.

Listening to some of the claims made for PTFE you might get the impression that it is the solution to almost any problem you might have, real or imagined. So why aren't the Big Oil companies putting it in their products?

Most of the oil companies are reluctant to discuss what is or is not in their oil. Off the record, however, many oil company spokespeople express concern that as a solid, PTFE does not stay in suspension forever. If the oil sits for too long the PTFE will settle out; an unacceptable situation for the oil companies we talked to. And as difficult as it is to get the PTFE in suspension in ideal situations, once combustion by-products and oxidation begin to change the chemical composition of the oil, keeping the PTFE in suspension poses a whole new set of problems.

Most oil company engineers also cited additive package balance as a major consideration. Whether talking about pour point depressants or oxidation inhibitors, each felt that whatever the gain in friction reduction the price was too high in other areas of lubricant performance.

If a PTFE additive sounds good to you, the best bet is to contact the manufacturer for test data that can be correlated against other known good lubricants. The Sequence IIID, Sequence VD, and L-38 tests previously mentioned, for example, are industry-wide standards that readily allow comparison against traditional lubricants. The manufacturer that can back up its claims with test results is a lot more convincing than the one with beautiful sales brochures filled with unsubstantiated claims.




Slick 50 and other engine oil additives supposedly reduce engine wear and increase fuel efficiency.

You may have heard the commercial or seen the ad:

Multiple tests by independent laboratories have shown that when properly applied to an automotive engine, Slick 50 Engine Formula reduces wear on engine parts. Test results have shown that Slick 50 treated engines sustained 50 percent less wear than test engines run with premium motor oil alone.

There are about 50 other products on the market which make similar claims, many of them being just duplicate products under different names from the same company. The price for a pint or quart of these engine oil additives runs from a few dollars to more than $20. Do these products do any good? Not much. Do they do any harm. Sometimes.

What's in these miracle lubricants, anyway? If they're so wonderful, why don't car manufacturers recommend their usage? Why don't oil companies get into the additive business? Where are these studies mentioned by Petrolon (Slick 50)? Probably in the same file cabinet as the tobacco company studies proving the health benefits of smoking.

The basic ingredient is the same in most of these additives: 50 weight engine oil with standard additives. The magic ingredient in Slick 50, Liquid Ring, Matrix, QM1 and T-Plus from K-Mart is Polytetrafluoroethylene. Don't try to pronounce it: call it PTFE. But don't call it Teflon, which is what it is, because that is a registered trademark. Dupont, who invented Teflon, claims that "Teflon is not useful as an ingredient in oil additives or oils used for internal combustion engines." But what do they know? They haven't seen the secret studies done by Petrolon (Slick 50).

PTFE is a solid which is added to engine oil and coats the moving parts of the engine.

However, such solids seem even more inclined to coat non-moving parts, like oil passages and filters. After all, if it can build up under the pressures and friction exerted on a cylinder wall, then it stands to reason it should build up even better in places with low pressures and virtually no friction.

This conclusion seems to be borne out by tests on oil additives containing PTFE conducted by the NASA Lewis Research Center, which said in their report, "In the types of bearing surface contact we have looked at, we have seen no benefit. In some cases we have seen detrimental effect. The solids in the oil tend to accumulate at inlets and act as a dam, which simply blocks the oil from entering. Instead of helping, it is actually depriving parts of lubricant" (Rau).

In defense of Slick 50, tests done on a Chevy 6 cylinder engine by the University of Utah Engineering Experiment Station found that after treatment with the PTFE additive the test engine's friction was reduced by 13.1 percent, the output horsepower increased from 5.3 percent to 8.1 percent, and fuel economy improved as well. Unfortunately, the same tests concluded that "There was a pressure drop across the oil filter resulting from possible clogging of small passageways." Oil analysis showed that iron contamination doubled after the treatment, indicating that engine wear increased (Rau).

the FTC and Slick 50

In 1997, three subsidiaries of Quaker State Corp. (the makers of Slick 50) settled Federal Trade Commission charges that ads for Quaker State's Slick 50 Engine Treatment were false and unsubstantiated. According to the FTC complaint, claims such as the following made in Slick 50 ads falsely represented that without Slick 50, auto engines generally have little or no protection from wear at start-up and commonly experience premature failure caused by wear:

"Every time you cold start your car without Slick 50 protection, metal grinds against metal in your engine."

"With each turn of the ignition you do unseen damage, because at cold start-up most of the oil is down in the pan. But Slick 50's unique chemistry bonds to engine parts. It reduces wear up to 50% for 50,000 miles."

"What makes Slick 50 Automotive Engine Formula different is an advanced chemical support package designed to bond a specially activated PTFE to the metal in your engine."

In fact, the FTC said, "most automobile engines are adequately protected from wear at start-up when they use motor oil as recommended in the owner's manual. Moreover, it is uncommon for engines to experience premature failure caused by wear, whether they have been treated with Slick 50 or not.