noise under dash

[bluemane500]

hey guys, my 79 is making a squealing noise under the dash at around 70 mph,sounds like a bad blower motor, its very annoying, anyone ever have this problem? its not the blower i disconnected it and the noise still comes at 70, it definitely from the driver side under the dash

[Mrmerlin]

try turning off the HVAC system and roadtest it sounds like a leaking vacuum pod under the dash/console

[bluemane500]

its a hard thing to find, it doesnt make the noise till i hit 70 and at that point i cant stick my head under the dash to find out whats making the noise, you mention vaccum, the funny thing is before i took the entire car apart my locks worked by vaccum, when i put it back together no more vaccum locks, the only thing still disconnected is the cruise control can under the left fender, as i mentioned i did disconnect blower motor and test drove and the noise was still there, please be more specific as what to disconnect,the noise is loud like an alarm of some sort

[Landseer]

There is some kind of O2 sensor timer that buzzes on the early cars, but isn't it near the passenger side somewhere?

There is a motorized unit for a damper near the driver's knee, too.
Not sure how that works. I think it has vac and motor.
I've got one that is apparently broken according to the previous owner, but haven't dove into that project yet.
Haven't heard a noise.

The center vent on pre 84 has a motor. I've had 86 diagphram break slightly and vibrate in center vent, depending on speed and HvAC slider setting.

There is a electric motor behind the little round grate on the console. But its real light duty. Not sure if it could support a bad bearing or other restriction and make noise.


There isn't much else up in there to buzz/alarm. Mystery / hard to know how to approach this one, but interested in outcome.

The seat belt warning is another possibility in console.


its not unusual for noises to antennuate within the car and seem like its coming from another zone.

Blower motor is passenger side on left drive car.

Sorry, can only speculate on this one.

[MPDano]

Originally Posted by Landseer

There is some kind of O2 sensor timer that buzzes on the early cars, but isn't it near the passenger side somewhere?

Yup, this is under that cover on the right side of the Passenger Front Seat. It doesn't buzz, but it clicks when it's over a certain miles. I think it's 60K. I just unplugged mine.

[bluemane500]

there were two vaccum lines that went to the headlights,some type of adj system, i didnt feel the need for them so i tied them together with a hose in the wheelhouse, i thought i was keeping the vaccum contained, maybe this is making a noisy vaccum pod, if i pull the cluster will the car still start and run,?that way i could see where the noise is coming from, given the speed it takes to make the noise i wonder if it is an airleak through the body or winshield,like when you blow over the top of a bottle

[neil30076]

Originally Posted by bluemane500

there were two vaccum lines that went to the headlights,some type of adj system, i didnt feel the need for them so i tied them together with a hose in the wheelhouse, i thought i was keeping the vaccum contained, maybe this is making a noisy vaccum pod, if i pull the cluster will the car still start and run,?that way i could see where the noise is coming from, given the speed it takes to make the noise i wonder if it is an airleak through the body or winshield,like when you blow over the top of a bottle

Those are the lines that allow you to adjust the headlamp aiming on a euro, which you obviously have. Ihad them on my 84 euro, just cut them off and pulled them out - didn't see anywhere to cap them off. Yes, you can start and drive without the cluster in place. Are you sure you have the vacuum lines routed correctly also, as you said you disconnected the cruise control - how did you terminate the vacuum line to it?

[bluemane500]

i never terminated it , i thought i connected all the vaccum lines , i only left one cable unconnected that goes under the intake , i think its the speed adjuster, i just left it in the engine compartment tied off to the side till i reseal the intakes, but i obviously left something disconnected because i dont have central locking anymore,,, seemed like a minor issue after everything i went through,, the noise is actually keeping me within the speed limits ,

[Mrmerlin]

remove the blue valve thats attached to the brake booster see if it flows in only one direction, then plug the small hose directly onto the booster and roadtest
in my previous suggestion was to put the HVAC system controls to off,
that is both knobs all the way left and the blower motor turned to 0

[bluemane500]

okay , i will check the valve on the booster and road test i will also make a video so you can hear whats going on here,, thank you for the input

[Landseer]

That blue valve. Forgot about it. Curious of outcome.

The euro headlight aiming system used mineral oil I think and not vac.

[bluemane500]

well i havent had a chance to diagnos the noise on the 79 yet but my 85 is now making the same noise but not as loud, it is in the hvac,, i didnt hear it till i added the 134 the other day, and then it started when i turned on the fan only for a short time on the 85,,, and it doesnt have anything to do with the 134 ,just coincedence i guess because the 79 ac is inop right now

[Mrmerlin]

that squeal is the setting motor for the HVAC just enjoy it it took 25 years for it to learn how to sing

[bluemane500]

i dont mind it on the 85 it goes away quick but my 79 it howls at 70mph you cant think over the noise very irratating its under the pod on both cars

[bluemane500]

is there a solution?