GM Longroof Forum
Would you like to react to this message? Create an account in a few clicks or log in to continue.



 
HomeHome  PortalPortal  GalleryGallery  Latest imagesLatest images  SearchSearch  RegisterRegister  Log in  

 

 Hissing noise, heat only blows out vents...

Go down 
3 posters
AuthorMessage
Boomhauers_93Wagon




Posts : 91
Join date : 2012-03-07
Age : 35
Location : Pittsburgh, PA

Hissing noise, heat only blows out vents... Empty
PostSubject: Hissing noise, heat only blows out vents...   Hissing noise, heat only blows out vents... Icon_minitimeTue Oct 09, 2012 12:45 am

Welp before I left this morning I started my wagon up, but only a few moments after there is a hissing noise from inside somewhere...

I also tried to turn my defroster on and it did blow, but only out the vents.

Anyone have any ideas?

Thanks in advanced as always!
Back to top Go down
sherlock9c1




Posts : 2373
Join date : 2009-05-28
Location : Huntsville, AL

Hissing noise, heat only blows out vents... Empty
PostSubject: Re: Hissing noise, heat only blows out vents...   Hissing noise, heat only blows out vents... Icon_minitimeTue Oct 09, 2012 9:11 am

My wagon makes a hissing noise in floor or off positions only. I'm wondering if either a vacuum hose came off under the dash or one of the piston seals failed.
Back to top Go down
Boomhauers_93Wagon




Posts : 91
Join date : 2012-03-07
Age : 35
Location : Pittsburgh, PA

Hissing noise, heat only blows out vents... Empty
PostSubject: Re: Hissing noise, heat only blows out vents...   Hissing noise, heat only blows out vents... Icon_minitimeTue Oct 09, 2012 10:41 pm

My hissing is from when I turn it on until I turn it off...

I tried looking under the dash with no luck, I'm assuming I have to take the whole dash apart?
Back to top Go down
sherlock9c1




Posts : 2373
Join date : 2009-05-28
Location : Huntsville, AL

Hissing noise, heat only blows out vents... Empty
PostSubject: Re: Hissing noise, heat only blows out vents...   Hissing noise, heat only blows out vents... Icon_minitimeTue Oct 09, 2012 11:39 pm

You can't locate the hissing noise? Use a 3-foot length of clear 3/8" tubing from a hardware store as a directional microphone - stick one end in your ear, then poke around under the dash with the other end. I've used that to pinpoint noise sources.
Back to top Go down
uxwbill

uxwbill


Posts : 319
Join date : 2012-08-01
Age : 41
Location : Illinois

Hissing noise, heat only blows out vents... Empty
PostSubject: Re: Hissing noise, heat only blows out vents...   Hissing noise, heat only blows out vents... Icon_minitimeTue Oct 09, 2012 11:40 pm

Boomhauers_93Wagon wrote:
My hissing is from when I turn it on until I turn it off...

I tried looking under the dash with no luck, I'm assuming I have to take the whole dash apart?
You have a vacuum leak somewhere. A hose could have popped off, but more likely than not, one or more of the vacuum hoses has finally degraded and is now leaking. There's also a vacuum reserve tank under there somewhere.

Going from memory...you have to take the dash trim off. That's probably the easiest part. A few screws, careful removal (as the assembly is fragile) and you're free. To get at the climate control head requires removing the ashtray and cup holder (four screws, wiring harness). Actually removing the climate control head requires that you first disconnect the linkage operating the cold/hot blend door. GM says that if you don't, you will break the cable off at the blend door.

There is a repair for this mentioned in the service manual if it does happen, but it sounds tedious and probably requires taking even more stuff apart...so I'd highly recommend not breaking it. You're supposed to be able to press in a retaining clip to let the control cable come loose (you can see it from underneath). I ended up breaking the retaining clip, but that seems far less serious, as the cable is held in place by other means and isn't too "inclined" to move around.

Then you can remove the climate control head and inspect those vacuum lines. There are two sets...one large set that governs all of the main climate control air directing operations and another, smaller set that controls the recirculation mode. The vacuum reserve tank is supposedly somewhere around the A/C evaporator (not sure if you have to remove it--but I hope not!). At the end of the vacuum lines furthest from the climate control head, you will find a plastic block that all of them run to.

My wagon has a vacuum leak somewhere in the dash. While the controls still work fine, I can hear the leak and vacuum loss when I shut the key off. I haven't looked into this yet.
Back to top Go down
http://greyghost.mooo.com/
Sponsored content





Hissing noise, heat only blows out vents... Empty
PostSubject: Re: Hissing noise, heat only blows out vents...   Hissing noise, heat only blows out vents... Icon_minitime

Back to top Go down
 
Hissing noise, heat only blows out vents...
Back to top 
Page 1 of 1
 Similar topics
-
» 93 RMW heating blows cold air. Everything else seems to work. HELP
» Airflow not always to right vents
» HVAC controls "hissing"
» a/c blows very weak
» Horn blows all the time.

Permissions in this forum:You cannot reply to topics in this forum
GM Longroof Forum :: Longroof Tech :: Heating and Air Conditioning-
Jump to: