Sounds like its comeing from the mid, mainly hear it when the AC clutch is spinning, and you can still hear it if im parked, and you can hear it at all times, Plus it sounds like something is loose just dunno where the fk it is,



[Second problem]...... no fkin heat!, its -5 here and snowed 10" TODAY, just today alone and still snowing and i have no heat, i just flushed out my rad from water in the summer time, and put in Anti freeze so i don't blow/crack anything. and i had heat for a bit after that, then i plugged in my truck to charge my battery and easier to start my tuck in the morning. Then after about 3 days i have absolute no heat what so ever still blowing extremely cold air, even when my truck is at idle and 90-100Deg C, even after driving for 3 hours still no heat!

 

Shot in the dark, investigate your defrost switch, maybe pop it from the panel and spray it real good with electric contact cleaner.

 

Did you run truck with out cap and heat on max till truck was hot to get air out of cooling system then refilled after flush? If yes i would pull heater core hoses and flush heater core by it self. People loved to mix dex cool with green antifreeze and it always ends up with a gunky mess.A good way to tell is to feel heater core hoses going into firewall see if both are hot. If that's not it, it may be a actuator in dash. As far as noise if im not mistaken it sounds like a rattle on exhaust maybe cat heat shield on top side mine fell off 6 months ago, rattled for a year before that. Oh and yes my blazer is a rust bucket lol

 

Well thanks , i added antifreeze until it was at the top, but i didnt bleed my system, there wasnt enough getting to the heater core to fill it up, it was just all air i have hot air now, thanks man , plus ill most likely just blow the **** out of the heater core anyways

 

Good, glad I can help im new at this forum. Did you also find that noise?

 

The noise sounds like the cat has broken-up inside. Take your hand and give the cat a couple of light raps....if you hear the same rattle....time to replace the cat.

 

- No i haven't still rattling and my belt is starting to sequel, but i know how to fix that and the noise is still on going but im pretty sure im getting a exhausts for Christmas or money

-Thats what i was guessing something in the cat, i need a new exhaust anyways (Hopefully getting one for Christmas)

 

Like I said befor check heat shield for cat they come apart at seam they are just spot welded.

 

+1 cats are breakin up love florida since i cut it off ran a rod thru broke it up then re welded it back on we have no emissions so might be different story for u.

 

No heat flush your heater core drain the rad disconnect both hoses leading to firewall add C.L.R. let sit 10 to 15 mins flush out refill you should then have heat and lots of it