I have an '08 3.8. My first one lasted ~137,000km to 2015. The replacement failed after 25,000km, (3 years in 201
,* & the new one is still good at 188,000km, 4 years.
* I didn't flush & fill the system correctly the first time, so likely had contamination that caused the early failure. The second time was from a different shop & they gave me good instructions on how to do it properly.