Hi guys. i have a 99 sierra 1500 4x4, about 125k on it now, runs super strong, better than when i bought it.

i have a AEM CAI, Wheatley Tune, E-fans, and magnaflow exhaust.

in December my heat started to diminish in my truck, so i took it to the dealer, only thing in town here really that i trusted, and had them do a coolant flush. i got my heat back but, now i have a squeak/ squeal in the interior of my truck, sounds like its coming from the dash, on any rpm over 1800. basically at 1800 it starts to chirp and then after that towards 2500 - 3000 it starts to squeal, but the heat works fine, and its never over heated or anything like that.

So whats the best option here??

I was thinking after searching the forums, that i will try and replace both the hoses and fittings to the heater core and flush it again just to hopefully make sure that there is nothing else in side. (By the way i took it back to the dealer after having the first flush, and made them backflush the heater core because it was making noise, but that actually seemed to make it worse than it was, or rather louder.)

any help is greatly appreciated. I just am to the point where i cannot stand the noise anymore. i know i can bypass it, but id rather fix it now, then try and fix it when winter hits.

thanks.

 

I've never heard of a heater core making a noise. Maybe the d-ship mech messed with the positioning of something...IDK.

 

ya, no one knows what it is. So for a temporary solution i went to menards and got a 3/4" brass ball valve with some barbed fittings on each end (8.99) and then two hose clamps, let the truck cool off a bit, cut the intake line to the heater core in half, out in the valve, tightened it down and for now, no heat but, no noise. I just dont have time to take the entire dash apart, nor do i have the money to pay for it.

 

I've heard of gurgling noises coming from the heater cores of these trucks, but this is the first time that I've heard of a squealing. I guess that if there's a blockage it could happen though...our sink at home makes a whistle with the hot water on and the valve open partially.

 

Any signs of a leaking core...steam out of the vents,etc. ? Good "temp fix" BTW.

 

no leaks, no steam, no nothing. coolant level is always in the exact same place, all i can think of is that it is still clogged or something. when i do my cam swap ill take off the hoses and flush some water through there, otherwise ill just live with the ball valve, and open it slightly in the winter when i want some heat.

it is the goofiest noise ever.

the dealers immediate answer was " new heater core" 1000$ screw that. ill spend the million hours taking the dash apart to replace a 90 dollar part before i spend a 1000 having them do it. only to probably have something else wrecked.

worst part about it is where it sits in the truck.

 

Maybe there's some debris lodged somewhere that causes those sounds...Murphy's Law strikes,perhaps...

Changing the core will be a pain but what heck? I would not pay them to do it either.

 

ya thats what im thinking, it will recieve a good flushing in a month or so when i do the cam. for now, i dont need heat, its 80's up here now. windows down tunes up thats all that matters.

 

Good luck.