Vacuum noise when turning car AC on.

10

Asked by May 30, 2013 at 08:10 PM about the 2007 Mercury Grand Marquis LS Premium

Question type: Maintenance & Repair

My car AC works fine but ive noticed when the AC is turned on I hear a steady vacuum
noise that comes on. Its pretty noticeable and fairly loud. When I turn the ac off I still
hear the noise until I turn the car off. If I don't use the ac I don't hear the noise at all. I
see no leaks from the vehicle. Any suggestions what could be causing this?

5 Answers

55

Some of the heater/ac controls are vacuum operated. I'm not sure if they are on your car but this could be a starting place. Good luck, J

2 people found this helpful.
29,835

Yes they are vacuum controlled on yours and there is probably a small leak in the lines under the dash or in a actuator.

2 people found this helpful.
775

The sound you hear could be the cooling fans kicking on. When the A/C compresser starts, strain is put on the engine and it heats up. The rad. fans kick on to keep everything cool. They will often continue to run until the key is off.

1 people found this helpful.
35

I also think it is a vacuum leak possibly in the A/C control unit on the dash.

1 people found this helpful.
185

Check on the bottom of the steering column there is a vacuum controlled switch that releases the parking brake when you put it in drive (even though it has a manual release) I would start there thats where my leak was and I myself didn't know it had one you didn't state what year your car was my is a 1987 Mercury Grand Marquis.

3 people found this helpful.

Your Answer

Grand Marquis

Looking for a Used Grand Marquis in your area?

CarGurus has 1,192 nationwide Grand Marquis listings starting at $1,200.

ZIP:

Mercury Grand Marquis Experts

  • #1
    Tracy Hooks
    Reputation
    5,980
  • #2
    kbro
    Reputation
    2,210
  • #3
    Js08016
    Reputation
    2,040
View All

Related Models For Sale

Used Lincoln Town Car
24 Great Deals out of 1,358 listings starting at $1,995
Used Ford Crown Victoria
710 listings starting at $1,700
Used Chevrolet Impala
397 Great Deals out of 25,595 listings starting at $799
Used Cadillac DTS
39 Great Deals out of 1,357 listings starting at $2,995
Used Ford F-150
2,344 Great Deals out of 215,477 listings starting at $1,300
Used Dodge Charger
242 Great Deals out of 32,689 listings starting at $1,800
Used Chrysler 300
313 Great Deals out of 19,328 listings starting at $1,899
Used Chevrolet Tahoe
528 Great Deals out of 36,655 listings starting at $1,375
Used Ford Mustang
270 Great Deals out of 37,082 listings starting at $2,150
Used Ford Taurus
186 Great Deals out of 15,917 listings starting at $981
Used Toyota Camry
761 Great Deals out of 70,900 listings starting at $1,200
Used Honda Accord
424 Great Deals out of 101,059 listings starting at $1,200

Used Cars For Sale

2007 Mercury Grand Marquis LS Premium For Sale
6 Great Deals out of 74 listings starting at $1,200

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.