In May 2021, as the 168 bus was completing its route to drop off children from Cloverleaf Elementary School in Statesville, the bus driver and instructor noticed smoke coming from the engine.
This smoke quickly turned into fire. The bus driver tried to use the fire extinguisher on board, but it was not enough.
Soon the bus was engulfed in flames that spread from the engine to the rear of the bus, including the roof and undercarriage.
Firefighters had to be on the scene to put out the flames, sending thick black smoke into the air.
The incident upset administrators at the Iredell-Statesville school, who were grateful there were no children on the bus. Ricky Adams, who runs the area’s bus garage, said one possible cause of the fire quickly became apparent: diesel buildup in the engine oil.
The 168 bus is built by International and has a MaxxForce engine.
The lawsuit against the parent company of International Navistar International Corp. and a complaint from Iredell-Statesville executives describe what critics say is a known design flaw that could increase the likelihood of too much diesel in the engine oil. This is an issue that could lead to increased maintenance issues or lead to engine fires.
An analysis by the NC Watchdog Reporting Network of hundreds of fuel sample records from school buses equipped with MaxxForce engines across the state showed that oil sample testing found fuel in the oil more than a third of the time.
The company did not respond to multiple requests for comment on engine issues sent to media email addresses listed on its website, either for this story or for Previous reporting by Network member WBTV in Charlotte Last year.
Despite known problems, state education officials have taken a hands-off approach to the issue. But some school districts have been working hard to replace the MaxxForce engine.
That includes Wake County, where the company paid about $20,000 to $32,000 as of 2016 to replace nearly all of its 149 MaxxForce 7 engines, according to spokesman Matt Dees.
The school system is monitoring the remaining nine MaxxForce 7 engines “to determine the best time to replace them,” he said.
“Our mechanics are skeptical of them”
In North Carolina, state data shows that starting in 2021, about 1,300 school buses with MaxxForce engines will be assigned to public school districts. Of these, about 400 buses are fitted with MaxxForce 7 engines, like those used when bus number 168 caught fire. Nearly 900 buses are equipped with MaxxDT engines.
All MaxxForce engines pass exhaust through the engine to burn off excess emissions to meet federal standards.
Diess said this act of forcing excess fuel into the oil system “caused excessive wear on internal engine components, leading to premature failure.”
The process has been criticized in at least six lawsuits across the country, including a class action lawsuit brought by tractor-trailer owners who claim the exhaust system caused the engine to fail. Navistar settled the lawsuit for $135 million in early 2020.
Iredell-Statesville school officials believe a mechanical issue may have contributed to the May 2021 fire.
Adams, who runs the bus garage, pointed to fuel saturation in oil as evidence of the problem.
Adams said the bus that caught fire underwent an oil change the day before the fire. The mechanic who changed the oil took an oil sample and found that the fuel was 30% diluted. This means that 30% of the oil is actually diesel fuel.
Adams said that number should be zero.
After the fire, mechanics took oil samples after more than 200 miles of oil changes and found a dilution of 37 percent.
“There are seven liters of fuel in the engine oil,” Adams said.
The NC Watchdog Reporting Network analyzed hundreds of pages of fuel lab reports from school systems across the state from 2018, which were provided in response to public records requests.
In counties that provide registrations for all MaxxForce buses in their fleets – Onslow, Brunswick, Northampton, Duplin, Davie, Montgomery, Washington, Martin and Iridel-Statsville – – Data shows fuel dilution issues requiring action occur about 40% of the time.
The results represented just over 50 buses in nine school systems, an analysis limited by a lack of response and data gaps in some school districts.
Adams advised the school district not to use any other Maxx7 buses until the problem was identified.
“Our mechanics are suspicious of them, afraid of them,” he said. “Honestly, I myself am a little scared of them right now, just because we don’t know exactly what happened to this guy.”
No state action despite potential dangers
In Statesville, the burnt out bus in the area is now covered in the back of the pit lane.
According to Adams, Navistar did not come to inspect the bus; he only sent a photographer to take pictures.
Iredell-Statesville School Superintendent Jeff James said it wasn’t a pretty sight.
“Watching it makes you shiver because some kids probably died on that bus,” James said. “Now is not the time to start trying to protect yourself, it’s time to say, ‘What’s wrong? Let’s fix this.'”
But the engine, like As reported by WBTV in August 2021, Never faced a corporate recall.
State education officials from the North Carolina Department of Public Education have repeatedly said the agency has no responsibility to warn of other potential danger areas, though a An agency spokesperson told WBTV last year that staff were monitoring the issue.
“While the NCDPI advises school districts on equipment maintenance based on the NC School Bus Fleet Handbook, the agency has no day-to-day oversight and instead refers to the experience and expertise of local staff,” spokeswoman Blair Rhoades said in an August statement. .
“These preventative maintenance procedures – including oil analysis and oil level and condition checks – are designed to keep the bus safe and allow technicians to report issues that may require additional monitoring,” the statement continued. “Districts will use As a result of these scans, informed decisions about the condition and operation of vehicles are made.”
Iredell-Statesville School is removing buses with Maxx7 engines from service. That means the district will have to find more buses with its own money — a price worth paying for student safety, James said.
“It’s serious. Someone has to take it seriously in every way,” he said. “I think we’re trying to sound the alarm and say there’s a problem.”
This story was reported and edited by Kate Martin, Shelby Harris and Ben Sessoms of Carolina Public Press; Sara Coello of The Charlotte Observer; Tyler Dukes and Jordan Schrader of The News & Observer; WBTV’s Nick Ochsner and Joseph Collins; Michael Praats of WECT; WRAL’s Travis Fain and Ali Ingersoll; and Jason de Bruyn of WUNC.
How We Analyze Hundreds of Pages of Fuel Reports
Earlier this year, the NCWatchdog reporting network asked every public school district in North Carolina for oil sample test results for school buses equipped with MaxxForce engines. The aim is to verify records of high fuel dilution results, which experts say can create safety and maintenance issues.
Of more than 90 school systems equipped with MaxxForce motors, about two dozen have provided recordings.
Journalists removed examples of duplicate reports and any reports from non-MaxxForce engines or ambiguous make and model engines. The reporter then tracked the number of times fuel dilution had been reported as a problem requiring corrective action to service the engine, usually an oil change or additional inspection.
If, according to the state Department of Public Education, the number of buses equipped with MaxxForce engines on file does not match the number of buses, data for a particular school system will be suppressed, which may indicate a deficiency in testing or documentation.
The results records included about 350 tests on about 50 buses from the Onslow, Brunswick, Northampton, Duplin, Davie, Montgomery, Washington, Martin and Iredell-Statesville school systems.