Installing The Oil Cooler In The Oil Cooler Box

Yesterday, while waiting for the paint on “the comb” for the cabin heat Bowden cable to dry, decided to move on and begin working on the oil cooler. Many months ago, portions of the oil cooler box were riveted together and painted ... so yesterday the oil cooler was installed in the box. Two beads of high temperature silicone are to be laid down in the frame prior to inserting the oil cooler.

Two beads of high temperature silicone are to be laid down in the oil cooler box in line with the flat surfaces on the oil cooler my fingers are pointing at.


With the oil cooler seated in the beds of silicone, the two large nuts are tightened down on the threaded pipe protruding from the oil cooler to secure the oil cooler to the cooler box. Next, two AN fitting adapters are screwed into the threaded hole on the oil cooler. Because the adapter fittings have straight threads, fittings also receive a copper crush washer … in addition, the use of Loctite 243 (blue) thread locker is called for.

The adapter fittings that will screw into the oil cooler require copper crush washers along with an application of blue Loctite 243 thread locker.


Fortunately, these adapter fittings are shown in the Rotax Illustrated Parts Manual and a torque specification of 26 foot pounds is given for the fitting. A ¾" crows foot wrench was used to torque the fittings. Fortunately, I was able to keep the crows foot at 90 degrees to the torque wrench so performing a torque offset calculation was not necessary.

Using the ¾" crows foot wrench adapter on the torque wrench at 90 degrees meant no torque offset calculations were required, so the desired torque of 26 foot pounds was dialed in and both the fittings were torqued down.


Moving on, the FF-1213 bottom is riveted onto the oil cooler box after two dollops of high temperature silicone are placed between the tabs on the FF-1213 bottom and the oil cooler. To keep things neat, a little masking tape was placed on the oil cooler to mask off where the silicone was being applied.

Cooler FF-1213 bottom prior to being riveted … High temperature silicone is to be placed on the cooler under in the area under the tabs on the FF-1213 bottom prior to riveting.

Using the pneumatic rivet squeezer to rivet the FF-1213 bottom onto the oil cooler box which completes the assembly of the box.

Completed oil cooler box enclosing the oil cooler.