I have a 99 Siverado is only blowing warm air, not hot. I took it to a dealer and they say the heater core needs to be replaced and want to charge $800+ to do it. I am not convinced it is the heater core. The truch warms up fine so I don't think it is the t'stat. I had a guy tell me my coolant system may need flushed and the heater core may just be clogged with something. I had another guy tell me he was told his heater core was bad, but it ended up being a ball point pin that had fallen into his defrost vent and keeping the damper from opening/closing properly. I know there is something in there because I have heard someting sliding around in there before. When I have the blower on #2 I can hear what sounds like something flappin in side the defrost vents, but it only does it on #2. I started to tear into the dash to see if I can get to the duct work, but what a pain. Can anybody give me thier thoughts on what may be wrong? Does anybody have some step by step instruction on how to take the dash apart? I have popped of the molding that goes around the radio and heater controls and popped off both side panels and removed the two screws. I can figure out how to get the handle above the air bag on the passenger side off.

Sorry for the long post, but any assistance would be greatly appreciated.

Thanks,
Cride

 

to get to the core,the dash comes out..all of it...steering column,everything.
are the hoses hot going to the core?..if 1 is hot and 1 is so-so,you've got a clogged core

 

Is that something that could be flushed with a garden hose after removing the heater hoses from the motor? Flushing in through the outlet of course.

 

Is there a way to check the hoses without taking the dash apart?

I am trying to take the dash apart myself to see if there is some debris keeping preventing the damper from opperating correcty, so any help in that area would be great as well.

 

check the hoses under the hood...where they head into the cab....they should both be hot...if one is hot and the other warmish,the core is clogged.

not to insult ya...but you can't take that dash apart...its an 8 hour job to put a core in

 

Thanks for the info.

I'm don't want to take the dash apart to replace the core, I am just trying to get to the duct work to see if there is anything in there. I thought if I could get the top of the dash out of the way, I could see down in there. Have you ever heard of something getting lodged in the duct and causing issues with the hot/cold dampener opperating correctly?

I noticed tonight that my heater is making noises when I turn it off and some times when I switch between blower/air output locations with the ****.

 

Okay, I did the hose test.

One was pretty hot, the other was just warm. Does this mean it is just clogged or could it be bad? The dealership wants to replace the core, but a local guy wants to replace the t'stat and flush the system.

What do you think? $800+ vs $100+.

 

if its clogged...ehh..Iusually flushing will quick-=fix it,or at least help...but it won't be as hot as a new core.
where ya live?..In Texas,a so-so heater is ok

 

I live in Missouri and a so so heater is what I have now. It probably blows in the mid to uppers 60s.

I will get it flushed and see what happens.

 

I just went through this same problem a month ago in my 98 silverado. I opened the black box under the glove box. Very easy. Just remove the 5-7 screws holding the bottom of the box to the top. then I saw the heater coil lying on the floor of the box. The air coming from the fan was blowing over the coil and not through it. I wired the coil back into the box because to tabs designed to hold the coil in were broken and reattached the bottom end of the box. Now I have solid heat. I didn't have to remove the dash to fix this.