[randall]

i am having a very similar problem with a 96 blazer 280k+ miles. i replaced the the water pump and it ran like a champ for a few months. i started noticing in nov that the air wasn’t heating up in the cabin. i decided to clean the heater core, and replaced the thermostat (no fail safe). at that point i noticed the temp wouldn’t get above 150 on the dash. the heat was more chilly than anything. i thought the new thermostat was faulty so i replaced it again. both are rated at 195 degrees. no luck. so i figured the coolant was too rich so i drained some and replaced it with water, now i am running a coolant mixture at -10 degrees F, which is still acceptable in my area. at that point i started noticing the temp would raise above 150. it would get to around 195 and then drop to 150. i am convinced that the thermostat is working, i can tell when it opens because it’s like a rush of cold water floods in. the air warm as the temp rises but becomes chilly when it drops to 150. oddly enough i have the cap off of the radiator and i can see steam come out of it, so i know it’s not cooling that much. the only other thing i could come up with is air in the system. so after wasting more time than i like to admit trying to find a bleeder bolt that doesn’t exist… i take it take it to the hill to try to burp the baby. i am still facing the same symptoms. it heats up until the thermostat opens. the only other thing i can come up with is the etc. it’s not that expensive, however i really do not want to open the system again without any evidence that the computer could be causing this some how. i did notice the fan is always running but has done that for as long as i can remember… perhaps this could be the issue but i don’t understand the significance. thought would be normal. can you explain more about how the fan maybe causing my issue? thoughts or suggestion that i have missed would also be appreciated. tks in advance.

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