hmm kinda... when you are overclocking a processor, especially the wolfdales, the vcore is really what 'kills' the processor - not so much the actual heat. i have mine @ 4.3 and it runs around 53 degrees on full load max fpu stress in prime 95 and thats the max temp i run it at. i personally dont like it running at 60 degrees or high but thats just ME. if memory serves correct the E8500 can run at 70-75 C and remain within limits of operation. btw max vcore is 1.36 so keep it within that if you plan on keeping it for awhile.
its not really the heat that kills... more the effect higher voltages have running through the cpu. that WILL reduce lifetime. however, unless you only upgrade every 5 years .... nothing to be worried about.