RV9 with just over 1000 hours.
The aluminum piece that the oil cooler is mounted to was found to have developed a long vertical crack in the bend area, running the length of the oil cooler, and the oil cooler then had play where it could move a bit (maybe 1/16") where the crack could open. At the top end, the crack had not yet completed its run, and it was the only thing left holding the oil cooler. This crack is in the aluminum sheet angle that the oil cooler is mounted to.
Observing the crack: Push the oil cooler aft with a little pressure. If there is a crack in the mount, it will open the crack a bit and the oil cooler will move a bit.
Repair: First I stop drilled the crack at the top end. Then I riveted on two doublers across the crack, one at the center (0.40 aluminum, a couple inches from the top), and a heavy one at the lower end, where the crack probably started. The doubler at the lower end is 1/16" angle. This repair made the oil cooler mounting completely solid, very strong.
It might be good to install the lower doubler before the crack can start to form.
The aluminum piece that the oil cooler is mounted to was found to have developed a long vertical crack in the bend area, running the length of the oil cooler, and the oil cooler then had play where it could move a bit (maybe 1/16") where the crack could open. At the top end, the crack had not yet completed its run, and it was the only thing left holding the oil cooler. This crack is in the aluminum sheet angle that the oil cooler is mounted to.
Observing the crack: Push the oil cooler aft with a little pressure. If there is a crack in the mount, it will open the crack a bit and the oil cooler will move a bit.
Repair: First I stop drilled the crack at the top end. Then I riveted on two doublers across the crack, one at the center (0.40 aluminum, a couple inches from the top), and a heavy one at the lower end, where the crack probably started. The doubler at the lower end is 1/16" angle. This repair made the oil cooler mounting completely solid, very strong.
It might be good to install the lower doubler before the crack can start to form.