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whistling sound in the HVAC system


richtazz
11-06-2010, 08:06 AM
I haven't posted a question on here in a while, but this one has me stumped. 99 GT with CJ2 dual zone auto climate control. I've had a whistling sound for quite some time (sounds like a tea-kettle whistle) in the HVAC system and it's really getting on my nerves. I thought it was the blower motor, so I finally replaced it when it stopped working, installed a cabin air filter, no change. It changes pitch with blower speed, and sounds like it's coming from the center console area. All modes work, but the whistle doesn't change no matter if it's in defrost, bi-level, heater, vent. I also tried setting it to recirculate, and it still makes the same annoying whistle. any ideas?

BNaylor
11-06-2010, 08:33 AM
I bet its annoying Rich. Too bad you can't get a cup of hot tea out of it. :lol:

The only items that come to my mind is noise from the A/C evaporator core, heater core or something in the lower HVAC assembly. This is the worst case.

In the meantime try disconnecting the main incoming accessory vacuum line at that distribution block by the blower motor or the vacuum tank to see if there is any change or rule out a vacuum related noise.

tblake
11-06-2010, 11:50 AM
Got me stumped Rich,

Is it more of a hissing or whining?

I usually solve annoyances like that by turning up the lynyrd skynyrd on the radio!!!

richtazz
11-10-2010, 10:23 AM
Bob, that's a good idea. Since all modes work, I didn't think about a possible vacuum issue, it's definitely worth a try.

LOL Tim. That's what I normally do when I'm alone in the car, but the wife likes to do that annoying "conversation" thing, which precludes turning the radio up loud. The noise is EXACTLY like a tea kettle whistle, and does go up in pitch as the blower speed is increased, but also gets quieter "decibel level wise" as the blower speed increases. Maybe I'll try recording it and post it on here so you can hear it.

tblake
11-10-2010, 04:23 PM
Rich, do you have a cabin air filter installed? I've seen leaves get into the HVAC system and cause all sorts of noises.

BNaylor
11-10-2010, 05:09 PM
Tim check out post #1.

Rich I recall the lower HVAC assembly has seals that may degrade. When I did the heater core job in the Regal I replaced the seals since there was some coolant damage and some came off during the removal process. Man that section is a PITA to get to and remove. :banghead:

tblake
11-10-2010, 08:05 PM
Tim check out post #1.

Rich I recall the lower HVAC assembly has seals that may degrade. When I did the heater core job in the Regal I replaced the seals since there was some coolant damage and some came off during the removal process. Man that section is a PITA to get to and remove. :banghead:

Good call Bob. Sorry Rich.

I have selective reading and selective hearing sometimes. Natalie gets mad at me because I have the worse case of selective hearing everynight right when she gets home from work. Funny how that works out.

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