Navistar International Corp. (NYSE: NAV) is recalling more than 4,900 late-model Class 8 International LT and RH tractors because defective connecting rods could cause engine failure, stranding a driver in traffic.
The company knows of three instances in which a driver was stuck in a lane of traffic and dozens in which the driver managed to ease the truck to the side of the road. An engine knocking noise, rough idle or an engine warning light can alert a driver to an imminent engine shutdown.
No related crashes or injuries are known, Navistar Vice President of Service Mark Reiter told FreightWaves.
Behind the scenes
In a rare behind-the-scenes look at the analysis of a problem and the discussions of what to do about it, Navistar described what led to an April 30 safety defect report to the National Highway Traffic Safety Administration (NHTSA). The agency posted the recall on its website on Thursday.
“One of the things we did was reach out to some of these fleets’ call centers so we could find out what the driver actually reported,” Reiter said. “We wanted to understand whether there were safety concerns for drivers.”
Company investigators collected data for the 2018-2020 International LT and the 2019 and 2020 RH on-highway trucks with Navistar A26 engines. An estimated 13%, or about 640 trucks in the recall population, is likely to experience the issue. About five failures a week are being reported, Reiter said.
The suspect parts, made by Camtac Manufacturing, a Linamar Corp. subsidiary in Guelph, Ontario, connect the piston to the crankshaft. One of two Camtac machines making connecting rods was machined outside the design tolerance for straightness between February 2018 and June 2019.
Coincidentally, Navistar was onboarding a new supplier for the component when it learned in September 2019 of connecting rod failures in five trucks at one fleet, Reiter said.
“We accelerated that change, so within six weeks we went from first notification of an issue to being out of the supplier and into a different supplier so we were able to have clean connecting rods,” he said.
The connecting rod issue is what safety investigators call “infant mortality,” meaning it presents itself early in a vehicle’s life. The trouble spot is in the low 100,000s of miles. Trucks with higher mileage are unlikely to have the issue.
In the faulty connecting rods, the bushing material in the small end bore of the connecting rod can develop cracks or lose chunks of bushing material over time, leading to connecting rod engine failure, Navistar told the NHTSA.
“This is a fatigue failure,” Reiter said. “This is not a wearout mode.”
Determining the beginning of a defect is easy because of multiple failures. “The part you really want to get right is when does it end,” he said. Connecting rods are among Navistar engine components covered under a 500,000-mile warranty.
Even with a relatively high failure rate, Navistar was unconvinced the issue imperiled driver safety. After following a rigorous investigative process, the decision to conduct a safety recall was unanimous.
The company considered how to address the problem short of replacing the engines in 4,499 trucks in the United States and 410 trucks in Canada.
Navistar decided the best remedy would be a red dashboard warning light programmed into the engine control module (ECM) or by adding a sensor. Newer trucks could get a fix delivered over the air and skip a trip to a dealership.
“We [looked at] previous recalls where the remedy was to provide advance notification of a failure,” Reiter said. “We saw that some other manufacturers had done something similar.”
Navistar considered but rejected advising drivers against operating the trucks since 87% are believed to be free of the problem.
“One of the things that is unique about this recall is that the remedy is not to go out and replace every engine or connecting rod in the suspect population,” Reiter said. “Although the failure rate is high, we don’t think it’s high enough to do open-heart surgery.”
Navistar is still developing the warning light fix. Customers and dealers will be informed by letter by July 8 or sooner. The NHTSA recall number is 20V-255.