Lycoming has issued Mandatory Service Bulletin 632 that requires owners to check their engines for connecting rods that contain bushings that do not meet Lycoming Engine’s specifications within the next 10 hours of operation.
The bushings were manufactured between November 2015 to February 2017.
The Service Bulletin opens with a warning to owners: “You must complete the Required Action in this Service Bulletin. If you do not…and the connecting rod bushing moves out of place, the connecting rod can fail and cause un-commanded structural engine failure.”
The Service Bulletin contains a list of engine serial numbers that may be affected. It then explains what needs to be done to correct the situation.
The company estimates the work to correct the problem could take 12 hours for a four-cylinder engine and up to 20 hours for an eight-cylinder engine.