You gotta do all of the coolant lines and cooling items on the X5 if you ever expect to have piece of mind for a reasonable duration of time. When I purchased my X5 4.6is in 2016 it had no coolant leaks. When I ripped down the engine to do the guides this is when I was surprised with how soft all the coolant hoses were. Definitely cheap quality hoses from US vendors that supply the South Carolina BMW Plant. The hoses were just falling apart. I changed every hose, aux pump, water pump, thermostat, temp sensor, fuel pump, timing chain, expansion tank, tensioner, all new front cover seals, valley pan, clutch fan, etc. I did not change the radiator because the previous owner addressed this a few months before he decided to sell it. Yes its a lot but I like to know that I can drive this vehicle anywhere without much worry/fanfare. Been from Texas to Florida 3 times with this vehicle to visit my parents and has been a joy. Oh and the completely rebuilt front suspension up front and H&R sport Springs has contributed greatly to the awesome ride on long distance.