Drain the coolant.
Remove the oil filter.
Pic. 2.204. Removing the oil cooler: 1 - water hose; 2 - oil cooler housing
Remove oil cooler (pic. 2.204).
Use a clean rag to wipe the seating surface on the oil cooler.
Install in the reverse order of removal.
Check the oil level. Add oil if necessary.
Start the engine and check for oil leakage. If there is a leak, identify the defective part and repair or replace it.