To go Along with the Farewell, pics...

[AzNMpower32]

Originally Posted by M_Six

Expansion tank is circled. Either the radiator or the expansion tank will fail between 60-75k miles.

Yes, replace the radiator once you pass 75k miles since they're guarenteed to go south around 90k as mentioned before.

[M_Six]

I have a 740iL with the same engine. First radiator went at 71k. I replaced the radiator and expansion tank then. This past Friday, just after I passed 145k, the expansion tank blew out. I wouldn't wait until 75k. If the car is over 65k with the original cooling system, replace it. If you don't plan on keeping the car past 120k miles or so, go ahead and replace them with OEM parts. If you want to keep it past that, it may be better to go with the Zionsville setup.