Motorcoach operators report few problems three months after Minnesota became the first state to require all diesel fuel sold within its borders to be a 2 percent biodiesel blend.

Operators contacted by Bus & Motorcoach News say the switch to biodiesel has largely been a nonevent, although one operator said he had experienced problems with clogged fuel filters on his diesel-powered school buses.

Last month, trucking publications carried articles saying over-the-road truckers were reporting problems with clogged fuel filters after buying biodiesel fuel in Minnesota.

The reports apparently prompted some non-Minnesota-based trucking companies to warn their drivers not to refuel in Minnesota.

But of a dozen Minnesota bus operators contacted in mid-December, only one reported any problems. However, virtually all the operators said they were keeping a close eye on the impact of the fuel and checking fuel filters regularly.

Stan Holter of Richfield Bus Co/.Heartland Tours in Bloomington, Minn., is one of those operators watching for problems but so far has found none. He said a number of the coaches in his fleet have Fleetguard Fuel Pro filters, which have clear glass filter covers, allowing mechanics to see when a filter needs changing.

"Were monitoring it very closely," reported Larry Benjamin of Northfield Lines in Northfield, Minn. Like other operators, Benjamin said his company prepared for the introduction of biodiesel by changing filters before the fuel was mandated, starting Sept. 29.
One of the characteristics of biodiesel fuel, especially blends containing higher percentages of soybean or vegetable oils, is its solvency property. Biodiesel has a propensity to dissolve sediment and other crude that builds up in fuel tanks, lines and injectors.
Some biodiesel advocates have blamed the problems reported by truckers on Minnesota fuel suppliers drawing down supplies and, in so doing, draining sludge from the bottom of their storage tanks into the tanker trucks used to deliver fuel to retailers and other customers.

Tom Ready of Ready Bus Line in LaCrescent, Minn., said his company experimented with 20 percent biodiesel last summer and had a serious problem with plugged fuel filters. The 2 percent biodiesel has been much less problematic, he said.

Theres debate among users, fuel experts, and biodiesel advocates and critics over the issue of whether 2 percent biodiesel has high-enough solvency properties to flush out sediment that might clog fuel filters. Some truckers claim it does.

Ted Anderson of Anderson Coach of Frazee, Minn., didnt take any chances one way or the other. In the months leading up to the introduction of biodiesel, Anderson specd petrodiesel with additives that would clean out the fuel systems in his buses.

Dennis Heinze of Lake Crystal Coaches in Madison Lake, Minn., was one operator to report early problems with biodiesel. He said they had to replace fuel filters on company school buses much more often than they had expected. Only one of the companys motorcoaches had any problem.

Heinze speculated that the International engines in the company school buses may have fuel filters that are more prone to clogging than the filters on the Detroit Diesel engines in his motorcoaches.

Meanwhile, Minnesota operators are waiting to see how the 2 percent biodiesel performs when the state goes into its annual deep-freeze mode and temperatures drop to 40 and 50 below zero.

Ready said that when his company was running 20 percent biodiesel last summer, they put a batch in a freezer. When they took it out, it looked like a bucket of old bacon grease -- a thick collar of goop was layered at the top.