Volvo S80 A performance sedan that offers top notch luxury, outstanding handling and so much more.

vacuum pump makes a buzzing sound after cars off?

  #1  
Old 07-30-2010, 02:14 PM
Junior Member
Thread Starter
Join Date: Jul 2010
Posts: 13
Default vacuum pump makes a buzzing sound after cars off?

since i bought the car it has been making a periodic buzzing sound??? previous owner was clueless.... said it was self leveling suspension.... WHICH IT DOES NOT HAVE!!! haha
anyways its annoying and i dont think its normal....
basically after i turn the car off for about 5-8 minutes it makes this buzzing sound every 20-30 seconds or so???

do i have a vacuum leak or??? any help would be greatly appreciated!
 
  #2  
Old 07-30-2010, 02:16 PM
Junior Member
Thread Starter
Join Date: Jul 2010
Posts: 13
Default

oh and if you press the brakes when the cars off it immediately makes the buzzing noise.... and it goes on for a little longer
 
  #3  
Old 08-09-2010, 09:21 AM
Junior Member
Join Date: Aug 2010
Posts: 6
Default

did you get an answer on this? i have the same issue. and now my key sticks when i turn it off - especially if car has been driven a long time. and now the battery is draining from somewhere. i think it's all related, so i would like to hear what info you received. thx.
 
  #4  
Old 08-11-2010, 09:58 PM
Junior Member
Thread Starter
Join Date: Jul 2010
Posts: 13
Default

i know its bugging me big time!! im residing to believe that maybe its my brake booster as i heard that they tend too leak on these cars.....
thing is i dont hear anything that would lead me to believe that its that.... plus my brake assist works fine... so.....
any tests i can run??? anyone know what the vacuum reading should be at the booster???
 
  #5  
Old 08-13-2010, 11:29 AM
Junior Member
Join Date: Aug 2010
Posts: 2
Default

I think I have the same problem. When I turn the car off it makes an irritating buzz every 10 seconds or so. I hear it coming from the right side of the engine compartment which is essentially the back end of the motor itself.

I can't tell if its the vacuum tubes there or not, but it also sounds like its coming from the gearbox, which it shouldn't be.

I'm not sure why it does this but there don't seem to be any problems related to it other than the fact that it is extremely annoying.

It only seems to do it when the air intake on the left side is running, which also seems to blow air into the passenger area of the car
 
  #6  
Old 08-17-2010, 03:03 AM
Junior Member
Thread Starter
Join Date: Jul 2010
Posts: 13
Default

well if you want to locate the buzzing... its almost directly under your air filter. the pump and all that is there...

but as far as ive learned its making vacuum in the brake booster... and im guessing its not holding vacuum so it keeps on pumping..... only thing i dont get is why the hell does the booster need vacuum after the cars off????
 
  #7  
Old 09-15-2010, 12:33 PM
Junior Member
Join Date: Sep 2009
Posts: 8
Default

same issue here. I have been told by two dealers and an independent mechanic that it is the brake vacuum pump and it is normal. Mine also only started doing this recently.
 
  #8  
Old 09-16-2010, 09:29 AM
Junior Member
Join Date: Aug 2010
Posts: 6
Default volvo buzzing

so will a mechanic address this on the forum or do we just keep getting more and more people with the same issue but no idea of what to do?
 
  #9  
Old 09-16-2010, 08:08 PM
Junior Member
Join Date: Sep 2010
Location: Oxnard CA
Posts: 2
Default

Hey guys, it sounds like your brake vacuum pumps are running for a bit before the car goes to sleep (typically 10 minutes). If the pump is going on/off like that you might have a very small leak in the brake booster, or in the associated vacuum lines. I'd not go so far as to say its normal, ideally the brake booster shouldnt have any leaks. There isnt really a good way to test vacuum at the booster, when the car is running its going to have enough vacuum to overcome most leaks. What you can do it listen under the drivers dash for the sound of air leaking, and also when you push on the brake pedal. If you hear a constant hissing then its pretty safe to say the brake booster is leaking.

The main reason the pump stays active after the car is off is for safety, if you were ever in a situation where the engine shut off, the vacuum pump will still be there to provide safe braking effort.
 
  #10  
Old 09-16-2010, 08:12 PM
tech's Avatar
Administrator
Join Date: Sep 2004
Location: Orlando, Florida
Posts: 36,351
Default

The electronic valve inline could also be bad/broken.
 
  #11  
Old 09-17-2010, 12:00 PM
Junior Member
Thread Starter
Join Date: Jul 2010
Posts: 13
Default

well i tried the method of listening to hissing under the dash i didnt hear any leaks.
but a leak will still show up as less vacuum than usual wont it???

and what actually leaks in the brake booster??? gasket, seal? i mean i doubt its the booster itself right??

im thinking what if i disconnect the pump? will it allow me to pinpoint the culprit or would it just not even allow the car to start???
any thing i should watch out for???
 
  #12  
Old 09-18-2010, 08:28 AM
tech's Avatar
Administrator
Join Date: Sep 2004
Location: Orlando, Florida
Posts: 36,351
Default

The diaphram inside the brake booster goes bad.
If you just disconnect the pump you might have a hard brake pedal.
Have you followed the hoses yet and found the plastic valve inline with an electrical connector? Make sure the top half is not broke and hanging off.
 
  #13  
Old 09-19-2010, 09:27 AM
Junior Member
Thread Starter
Join Date: Jul 2010
Posts: 13
Default

yeah mine is okay. when i went to discover the noise i took it all out and all seems to be in good condition nothing was broken but yeah i think i might have a leaky booster, gave it a much closer listen and i heard that little hiss.... BAALLLS!!!

wheres the best place to get one? please dont say dealer.
 
  #14  
Old 10-01-2010, 11:54 AM
Junior Member
Join Date: Sep 2010
Location: Eindhoven, Netherlands, EU
Posts: 3
Default

My vacuum pump kept running when I put the key in ignition. I tested by pulling the tube that goes to the brake booster and covering the brake booster switch with my finger. The pump did not stop so I figured the switch was bad. Replaced the switch. Now after ignition it pumps for 1 or 2 seconds and then stops. Happy camper.
 
  #15  
Old 10-04-2010, 11:52 AM
Junior Member
Join Date: Aug 2010
Posts: 6
Default vacuum buzzing, etc

are either of these a big deal and/or need immediate attention? also, on another matter, my mechanic found that the wrong battery had been installed in my 02 S80 causing ac cooling, cruise, dead at startup, etc to just stop. since getting the correct battery with proper power for my car, this issue with the key not turning to off position to release and the sounds has reduced GREATLY!
 
  #16  
Old 05-03-2011, 05:16 PM
Junior Member
Join Date: Jan 2011
Posts: 23
  #17  
Old 05-03-2011, 05:17 PM
Junior Member
Join Date: Jan 2011
Posts: 23
  #18  
Old 05-05-2011, 09:02 AM
Junior Member
Join Date: Jan 2011
Posts: 23
Default Vacuum pump

if your Vacuum pump blows air out then its knackered
 

Last edited by mike1976; 05-05-2011 at 01:20 PM.
  #19  
Old 05-05-2011, 12:58 PM
Junior Member
Join Date: Jan 2011
Posts: 23
Smile Vacuum pump 1999 s40t4

pump running after turning car off took pump out and took it apart it was full of dust and rust cleaned it out put it back in the car now pump only go's on when it needs

to to check if your pump is working how it should let the pump run. then pull the air lines apart you should hear a pop from the suction if not then look for leaks then check the oneway valves buy blowing or sucking air in and out.
if still no fault found the pump switch and relay can be under the left hand side wheel arch you will need to jack up car and take the wheel off to make room to get to it . ps remember to check the fuse in the fuse box under the bonnet

job done
 

Last edited by mike1976; 05-05-2011 at 01:01 PM.
  #20  
Old 05-06-2011, 08:09 AM
Junior Member
Join Date: Sep 2009
Posts: 8
Default Interesting, (if not final) solution

I found that putting your foot underneath the brake pedal and pulling back a bit will make the noise stop immediately. I may be just masking a problem that will eventually require service, but it eliminates the noise and works for now.
 

Thread Tools
Search this Thread
Quick Reply: vacuum pump makes a buzzing sound after cars off?


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.