A Sarasota County, Fla., fleet technician has solved the problem of water contamination in auxiliary diesel fuel tanks, and Fleet Manager Greg Morris is implementing the solution across the County’s 68 auxiliary diesel tanks.

The Sarasota County fleet a few months ago began experiencing problems with some of its heavy equipment. Staff found clogged fuel filters and water in the fuel/water separator filters in off-road equipment, mostly Menzi Mucks and arm mowers, according to Donald (Troy) Smith, heavy equipment technician. The auxiliary fuel tanks (carrying ultra-low-sulfur diesel) deliver fuel to all the County’s off-road assets, but the problems have arisen mostly in equipment that require the most fuel.

“Assets were losing power or shutting down due to the contaminated fuel,” Smith said. The equipment operators first told fleet staff about the problem, and technicians could see water at the bottom of the filters. That last piece of equipment with water contamination was out of service for a week while fleet staff cleaned out the fuel system and changed all the filters twice. Operators are being asked to turn off the equipment and notify fleet staff if they sense contamination to prevent engine shutdown.

Smith developed a plan and worked with Morris, technicians, operators, and the shop manager to solve the problem. Staff members had to try various methods before they found the solution, including cleaning the equipment fuel systems, thoroughly cleaning the auxiliary fuel tanks, and checking the main fuel tanks at the fueling sites. Smith discovered the cause of the problem was not in the main fuel tanks, but in the auxiliary tanks themselves.

To solve the problem, Smith ordered three spin-on fuel filters for the auxiliary tanks: one 30-micron fuel filter, a 10-micron filter with a drain plug to drain water off, and a 10-micron filter with a feature that drops flow from 12 gallons per minute to less than 1 gallon per minute when contaminated by water. If the third filter fills with water, it will stop the fuel flow and shut down the engine, Smith said.

Smith then raised the original pick-up tube in the tank 2 to 3 inches from the bottom of the tank. He sealed all piping on the tank and welded a support bracket to hold the newly designed filter bank. He installed all three filters, made sure everything was sealed, and instructed operators to fuel the tanks every night in order to prevent condensation. He then made some modifications to the fuel tank so that any fuel dispensed from the auxiliary tanks will pass through the three filters. Karen Yeo, fleet business professional, added that the fuel already passes through a 30-micron filter and a 10-micron filter as it is being dispensed from the main fueling site.

“Hopefully this will clear up the problem,” Smith said. “So far it has on a couple of them.”

The filters cost $83 for all three, and it takes about an hour and a half to complete installation. Filters will be changed as the F-450 and F-550 trucks they sit on come in for regular preventive maintenance. Smith expects PM on the fuel tanks will take about 20 minutes.

Fleet staff has yet to determine the cause of the water contamination, but Morris said it could be attributable to an extremely heavy rain season and possible condensation. The fleet is currently checking with other neighboring fleets to see if they’ve experienced the same issue.

In the meantime, however, Morris has given Smith the go-ahead to begin these modifications to all auxiliary diesel fuel tanks. He believes this preventive measure is less expensive than replacing a diesel engine, which could cost up to $16,000. Smith has completed three modifications and will work on the rest as the vehicles come in for regular service.

By Thi Dao