With high diesel prices looking like they’ll be around for a while, many truckers might be tempted to give their engines a helping hand by spiking fuel tanks with additives. So, too, do the onset of winter and the threat of gelling fuel convince some truckers that it’s time to pour a bottle of magic goo into their fuel tanks.

But as markets go, the niche for the diesel additives available through truck stops and specialty shops-known in the petrochemical industry as the aftermarket, to keep from confusing the over-the-counter liquids with ingredients added at the refinery-is a pretty wild, loose and murky one.

Chevron notes that truckers use additives to keep rigs running in extreme cold, which could cause fuel gelling; as “cheap insurance for their big investment in equipment;” or, simply, because they feel the quality of diesel on the routes they travel is sub-par.

But as the company notes, these are both “real and perceived needs.” Many of the products are “aggressively marketed with testimonials and bold performance claims that seem ‘too good to be true.'” Often they are.

Simon Garner, director of sales and marketing at Stanadyne Automotive Corp., says diesel additives are popular in North America because the quality of the fuel is generally poorer then the diesel sold in Europe, where the heavier fuel is used not only in transport trucks and buses but also in a lot of cars.

“So much of the additives on the market are made by petrochemical companies, which know chemicals but don’t know diesel engines,” he says in a telephone interview. For that reason, Stanadyne, a 120-year-old maker of diesel-fuel filters, heaters and separators, decided 12 years ago to add an engine additive to its product line, Garner says.

He notes that the additives market is “huge” and agrees it has suffered a black eye because of snake oils-the kind of wonder products that are long on boast and short on delivery. “Many of these can cause more harm than good,” he warns.

Garner says the additives market “exploded” in 1993, after legislative changes in the U.S. pumped lower-sulfur diesels into the market, resulting in “a huge rash of fuel-related (engine) problems.”

And speculators saw dollar signs. “Anybody with a chemistry set in their back yard got into the additives market then.”

“There is a wide variety of diesel from town to town, and from station to station,” says Bob Brennan, product manager for Minnesota-based Conklin, a 30-year-old maker of additives and lubricants. Today, more than 150 operations pour out millions of gallons of the stuff, which some also call “fuel conditioners.”

A look around the Internet reveals a wide variety of additive brewers, some that also sell all-purpose cleaners, “deglazers”, and boiler and septic- system treatments. Maybe because the market is so crammed with a confusing variety of products and suppliers, heavy-truck engine manufacturers resort to across-the-board judgments.

“Essentially, Caterpillar does not recommend any additive,” says company spokesman Ray Hartwell. “If the fuel is deemed to have bacteria or wax buildup and clogs the fuel filter-and the engine loses power since there is no bypass for a clogged filter-the company recommends that the customer work with his diesel fuel supplier to resolve the problem.”

“That’s a pretty short answer from Mack,” says Greg Shank, a staff engineer with Allentown, Pa.-based Mack Trucks Inc. “We don’t approve of any of those.” Ken Clarke, power-train manager for Volvo Canada, adds “we recommend no additives.”

“It’s fairly explicit in one or two places in the (operations) manual.”

“Basically, what they’re saying is that you should have good fuel. In a perfect world, that’s possible, but then the real work isn’t perfect,” counters Tom Maguire, the vice-president of marketing at FPPF Chemical of Buffalo, N.Y., a company that markets additives.

His company has been in the additives business for 30 years, and has plenty of anecdotal reports on his product’s performance but lacks objective studies to back up those claims.

Stanadyne’s Garner, says the head of a major American trucking fleet once received an equally broad rebuff from a panel of engine manufacturers at a diesel-fuel conference after asking what they thought of additives.

“This guy then pleaded, ‘But then why is it that when I go into your outlets, you all sell bottles of the stuff with (your own brands) on them.'”

As for threats from manufacturers, such as warranties being nullified by the use of additives, Garner is clear. “Legally speaking, I don’t think they can categorically say one way or the other” that they can hurt an engine.

“Engine manufacturers don’t really put their stamp of approval on anything, since they’d be afraid to leave anyone out,” says Brennan. n