have had 2 break in same spot! Don't see any interference with anything else hitting it anywhere. Confused!
It is not uncommon. Can be from over tightening the fastener. That compresses the sheet metal under the head of the fastener and causes fractures, especially when subjected to engine vibrations. Some folks add a washer top and bottom to spread out the load. Larry
I used to see that a lot,Don't run without one.the oil pressure will be all over the place.yes I used a washer on both sides of the hole on each bolt.also I think they get brittle after many years of service.
