okay... it has been staying in the mid 90's to low 100's here.. my blazer idles at almost 225 degrees.... i thought this was normal because it was hot, but my father-in-laws truck idles at a nice cool 190 and he has a 327 v8! I am not sure what is wrong with my blazer. Sometimes if I travel 20-40 minutes at about 60-65mph, it will run at 220 and idle at 240, of course I shut it off and pop the hood to let it cool in the shade, but it is starting to get annoying!! what is wrong with my truck??? a blockage in the cooling system (due to dexcool mixing with other antifreeze)????? my thermostat is broken??? PLEASE HELP!!!! i must fix this soon!!!

 

its been hot here too. Mine climbs up to about 220 or so if i let it idle long enough, it stays about 190-210 when driving. Is your fan going into "direct drive mode" at 210? i made a post about the motor whistling whenever its over 210 and its the fan kicked it high gear.

 

no... mine actually makes this roaring sound when you take off from a stop at high temps... it quits roaring at around 10-15 mph...

 

Yeah, that's your engine fan making the noise. Checked the coolant level? Please don't say you've mixed DexCool with coventional antifreeze. Checked your coolant mixture ratio with an antifreeze tester? Done a pressure test?

 

good pressure, good coolant level, mixed dex-cool with the generic equivalent of dex-cool... but i dont know what the previous owners did, I know I flushed a nasty clog out of my heater core last winter, looked as if the previous owner had mixed dex-cool with conventional antifreeze, maybe there is another clog??? think I should just flush the whole system and refill with conventional antifreeze??

 

Not to point out the obvious, but your A/C condensor isn't plugged up with bugs or anything is it?

 

I dont believe so..lol wouldnt that cause problems with my A/C too??

 

I don't know if I trust 'generic equivalent of dex-cool'. I use Prestone 50/50 DexCool. On the back it says it is approved by GM for DexCool systems and lists the GM spec # (can't recall what that is right now). How old is the radiator cap? I use a 16lb Stant cap. If you want to flush and fill (I recommend staying with DexCool) by sure you do a real f&f. Open block drains, radiator petcock, wash out the overflow tank, turn on the heater full blast, and run lots of water through it to be sure you remove any non-Dex coolant.

 

prestone dex-cool equivalent is what I was referring to as generic dex-cool..lol

 

Not for nothing, but your comment about "roarin" peeked my interest. I just replaced the intake gaskets on my Blazer, super flushed the engine and cooling system, flushed the oil system and the roaring sound my Blazer made (akin to a jet engine when I took off from a stop) has greatly DIMINISHED. My wife hardly comments about the noise (and that's saying something, if you get the drift). My son who drives it mostly has also commented about how quiet the engine has gotten. Could be something, could be nothing. How's the oil level? I'd suspect bearing roar!