0k, listen up, this is important. I've been dealing with overheating issues all year with the Blazer. First I thought it was the thermostat, nope. I bypassed the heater, nope again. I had the system flushed, nope, still overheating. Then had the fan clutch replaced, BIG difference. seemed to take care of the problem right there. But then recently noticed coolant smell and overheating. turned off A/C to avert high temp, that worked for like a day, then it would overheat whenever. Investigated around the radiator and noticed dried and fresh coolant, followed coolant under fan shroud and behold! Big crack in plastic of radiator. STINK! 0k, pulled out bad radiator and something to note here; there was about 1/3 of the fins plugged with crap. fuzz, hair, bugs. this was never apparent because this is not readily visible because of the shroud and A/C blocking the view. I think this had a big part in reducing the systems ability to cool and may have contributed to other system failures. I know these Blazers run hot, but we have gone through 4 batteries the past 4 years. They just seem to burn up.

Update from Apr 11, 2010: March 2010, over heated again! Arg!!!! So I changed the thermostat. As I took it out It was covered in gunk, so maybe it was getting stuck. But then it turned back to winter so I havent had a chance to see if it overheats again.