Weird sound from dash, HVAC ?
12-13-2003, 11:34 PM
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Weird sound from dash, HVAC ?
Greetings,
First off, if anyone knows of a thread pre-existing on this subject, please tell me.
I have a strange sound coming from the drivers side of the dash. It sounds like it is pretty far up in it and I think it's probably a vacuum related leak. During any acceleration or load on the engine, I hear a sound like an old fashioned vacuum pump (kind of a quick pumping sound) that rises and falls according to what the engine is doing.
Performance doesn't seem to be affected in any way, it's just damn annoying from inside the car. Not very sporty sounding...
Is this just a sign that I need to replace all of the vac lines ? The car is an '89 and I think they have never been touched and I don't have any heat either. I have a new heater valve, but have not yet installed it.
One thing regarding the sound. It doesn't show up at first. The car needs to be warmed up first and then it gets louder. It's like I have a Keebler Elf in there.. hammering away at something. Thanks.
Rob
First off, if anyone knows of a thread pre-existing on this subject, please tell me.
I have a strange sound coming from the drivers side of the dash. It sounds like it is pretty far up in it and I think it's probably a vacuum related leak. During any acceleration or load on the engine, I hear a sound like an old fashioned vacuum pump (kind of a quick pumping sound) that rises and falls according to what the engine is doing.
Performance doesn't seem to be affected in any way, it's just damn annoying from inside the car. Not very sporty sounding...
Is this just a sign that I need to replace all of the vac lines ? The car is an '89 and I think they have never been touched and I don't have any heat either. I have a new heater valve, but have not yet installed it.
One thing regarding the sound. It doesn't show up at first. The car needs to be warmed up first and then it gets louder. It's like I have a Keebler Elf in there.. hammering away at something. Thanks.
Rob
12-15-2003, 08:33 PM
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I've been hoping you'd get a reply to this question, I've got the same problem... For me it sounds like a fillament is vibrating or perhaps a single blade of a fan is barely rubbing on something. It's been driving me nuts...
It does sound like it's coming from the right and behind the control gauges, or a little left and behind the HVAC. Sound happens for me typically when the gas is pressed, and I only hear it at idle when I first start the car.
If you ever get the answer, I'd love to know.
It does sound like it's coming from the right and behind the control gauges, or a little left and behind the HVAC. Sound happens for me typically when the gas is pressed, and I only hear it at idle when I first start the car.
If you ever get the answer, I'd love to know.
12-16-2003, 01:34 AM
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Well, guys, this sounds suspiciously like something I fixed on my car about three weeks ago. Major hassle, too.
Or (especially what you're describing, Blue), it might be as simple as replacing the vacuum check valve near the brake booster (see the first photo in John Pirtle's Vacuum Actuator write-up). The vacuum check valve can make a nasty "reed instrument"-like sound when it's going bad. This is literally a 5 or 10 minute job and $18 part if that's your problem.
If it's not that simple, though, read on...
I was getting a really nasty tapping sound from the center vent area that would come and go with engine vacuum, so I knew it was something vacuum controlled.
It's probably the same thing that a few other people have noted at
http://www.nichols.nu/tip439.htm
Now to determine whether or not you have vacuum leaks that might be responsible for this, follow the vacuum testing procedure that Wally Plumley gives (it's the last section of this multi-part tip):
http://www.nichols.nu/tip509.htm
Also make sure you read John Pirtle's most excellent Vacuum Actuators write-up. It was a huge help to me as I did my diagnosis and repair.
You'll need a vacuum tester (good thing to have on hand, given all the vacuum-related stuff on the shark). I had a major vacuum leak, which I finally traced to the "orange line" that feeds the center vent actuator. As it turns out, I had a little crack in the bladder on the center vent actuator's bladder.
FWIW, even if you have the same problem I did, the repair will be a little easier on your pre-'90 cars. The passenger airbag-equipped cars (I think they started in '90) make this job a little harder, because it's really hard to get to one of the bolts that holds the center console on, and it's also a lot harder to get the vacuum actuator's arm hooked back to the comb flap. I had to drill a big hole next to the actuator and then plug it back up with a big stopper. Have a good supply of beer on hand and save up some curse words starting a few days in advance.
The guilty party:
After bladder replacement (note rubber stopper to left of actuator, and remember, the hole and stopper isn't necessary for pre-passenger-side-airbag cars):
Also, if the problem does turn out to be this actuator, the replacement part will run about $30 to $35 from one of the big three.
Oh, finally, a "while you're in there...": since I had my glove box off, I replaced the glove box damper. I don't know if that part is on your model year (I think some of this stuff moved around when they put in the passenger air bag), but mine was quite worn out and the glove box would open and drop like a rock. New part gives it the nice "slow open" feature. $36 or so for the replacement part. Damper is hanging free in the center of the following photo. Click on it for a big version where you can see it better.
Or (especially what you're describing, Blue), it might be as simple as replacing the vacuum check valve near the brake booster (see the first photo in John Pirtle's Vacuum Actuator write-up). The vacuum check valve can make a nasty "reed instrument"-like sound when it's going bad. This is literally a 5 or 10 minute job and $18 part if that's your problem.
If it's not that simple, though, read on...
I was getting a really nasty tapping sound from the center vent area that would come and go with engine vacuum, so I knew it was something vacuum controlled.
It's probably the same thing that a few other people have noted at
http://www.nichols.nu/tip439.htm
Now to determine whether or not you have vacuum leaks that might be responsible for this, follow the vacuum testing procedure that Wally Plumley gives (it's the last section of this multi-part tip):
http://www.nichols.nu/tip509.htm
Also make sure you read John Pirtle's most excellent Vacuum Actuators write-up. It was a huge help to me as I did my diagnosis and repair.
You'll need a vacuum tester (good thing to have on hand, given all the vacuum-related stuff on the shark). I had a major vacuum leak, which I finally traced to the "orange line" that feeds the center vent actuator. As it turns out, I had a little crack in the bladder on the center vent actuator's bladder.
FWIW, even if you have the same problem I did, the repair will be a little easier on your pre-'90 cars. The passenger airbag-equipped cars (I think they started in '90) make this job a little harder, because it's really hard to get to one of the bolts that holds the center console on, and it's also a lot harder to get the vacuum actuator's arm hooked back to the comb flap. I had to drill a big hole next to the actuator and then plug it back up with a big stopper. Have a good supply of beer on hand and save up some curse words starting a few days in advance.
The guilty party:
After bladder replacement (note rubber stopper to left of actuator, and remember, the hole and stopper isn't necessary for pre-passenger-side-airbag cars):
Also, if the problem does turn out to be this actuator, the replacement part will run about $30 to $35 from one of the big three.
Oh, finally, a "while you're in there...": since I had my glove box off, I replaced the glove box damper. I don't know if that part is on your model year (I think some of this stuff moved around when they put in the passenger air bag), but mine was quite worn out and the glove box would open and drop like a rock. New part gives it the nice "slow open" feature. $36 or so for the replacement part. Damper is hanging free in the center of the following photo. Click on it for a big version where you can see it better.
12-16-2003, 12:14 PM
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Blue,
I am going to tackle it over the Christmas holiday, among a few other items that I have been putting off.
Ed,
Thanks for all of the great tips. I have Wally's paper on the HVAC system and I purchased a MityVac a while ago (in anticipation of someday having to do this). I have been reluctant to removing the center console because it always looked so complicated under there, but I guess that the time has come.
Since, my heater doesn't work and I have purchased a new radio also long ago... what better way to get a whole slew of items done at the same time.
I will post my results. Thanks again.
Rob
I am going to tackle it over the Christmas holiday, among a few other items that I have been putting off.
Ed,
Thanks for all of the great tips. I have Wally's paper on the HVAC system and I purchased a MityVac a while ago (in anticipation of someday having to do this). I have been reluctant to removing the center console because it always looked so complicated under there, but I guess that the time has come.
Since, my heater doesn't work and I have purchased a new radio also long ago... what better way to get a whole slew of items done at the same time.
I will post my results. Thanks again.
Rob
12-17-2003, 02:03 AM
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Thanks a bunch Ed! 
Vacuum check valve was cracked, replaced it, one problem down! Yay! Now having a vacuum inside the car, big whistle noise is worse than ever.
Replaced the "condom" in the foot well actuator (without removing the center console!), and I now have heat on my feet!!! woohoo
Fixing that actuator through the hole for the environmental controls reminds me of that joke about the female gyno repairing the engin through the tail pipe!
Vacuum check valve was cracked, replaced it, one problem down! Yay! Now having a vacuum inside the car, big whistle noise is worse than ever.
Replaced the "condom" in the foot well actuator (without removing the center console!), and I now have heat on my feet!!! woohoo Fixing that actuator through the hole for the environmental controls reminds me of that joke about the female gyno repairing the engin through the tail pipe!
