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

45

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 out of 2 people think this is helpful.
26,645

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

1 out of 1 people think this is helpful.
655

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 out of 1 people think this is helpful.
35

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

1 out of 1 people think this is helpful.
165

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.

2 out of 2 people think this is helpful.

Your Answer

Add photo

Related Questions

  • how to fix ac 2 answers

    the freon was low filled it up. the car has not ran hot at all. when I click the ac button to turn on the air or heat you can hear it click on but no fan noise or air blowing. what can i do to fix thi...

    2000 Mercury Grand Marquis LS

    -

    Maintenance & Repair

  • turned on the air conditioner in the car and the car sounds like it pulling 3 answers

    I WAS SITTING IN NTHE CAR AND TURNRD ON THE AIR CONDITIONER AND THE CAR STARTED MAKING A PULLING NOISE SO I proceeded to turn the car of then when I WENT TO DRIVE AGAIN IT SEEMS AS THJOUGH THE CAR WAS...

    1999 Mercury Grand Marquis 4 Dr GS Sedan

    -

    Maintenance & Repair

  • Where is the first place to look for vacuum leak on A/C heater stuck on defrost? 6 answers

    My Grand Marquis ac heater is stuck on defrost. I've read I should look for a vacuum leak? Where should I look? Do I need to pull the dash out? Replace vacuum switch? Do I look under the hood?

    2006 Mercury Grand Marquis

    -

    Maintenance & Repair

  • WHISTLE NOISE 1 answer

    VERY HIGH PITCH WHISTLE ALMOST A DOG WHISTLE COMES FROM UNDER THE DASH ONLY WHEN CLIMATE CONTROL IS ON EVERY THING WORKS THO COLD AC HOT HEAT DEF ALL FINE , DIDNT HAPPEN FOR MONTHS NOW ALMOST ALL THE ...

    2000 Mercury Grand Marquis LS

    -

    Maintenance & Repair

  • Knocking noise from air vent before turning a/c on 3 answers

    I get a loud knocking or ticking from inside passenger side dashboard when I start the car. Noise goes away immediately when I turn the a/c on. Any repair suggestions?

    2009 Mercury Sable Base

    -

    Maintenance & Repair

Grand Marquis

Looking for a Used Grand Marquis in your area?

CarGurus has 1,796 nationwide Grand Marquis listings starting at $500.

ZIP:

Search Mercury Grand Marquis Questions

Mercury Grand Marquis Experts

#1 Tracy Hooks
Tracy Hooks
Reputation 5,260
#2 kbro
kbro
Reputation 2,050
#3 Js08016
Js08016
Reputation 1,660
View All

Related Models For Sale

Used Ford Crown Victoria
12 Great Deals out of 976 listings starting at $2,990
Used Lincoln Town Car
28 Great Deals out of 1,818 listings starting at $1,995
Used Chevrolet Impala
618 Great Deals out of 29,205 listings starting at $1,300
Used Chrysler 300
374 Great Deals out of 20,560 listings starting at $1,000
Used Dodge Charger
250 Great Deals out of 27,349 listings starting at $1,997
Used Ford Taurus
194 Great Deals out of 19,158 listings starting at $1,495
Used Honda Accord
685 Great Deals out of 81,559 listings starting at $1,200
Used Ford F-150
2,400 Great Deals out of 208,535 listings starting at $895
Used Chevrolet Tahoe
609 Great Deals out of 27,568 listings starting at $600
Used Ford Mustang
301 Great Deals out of 45,096 listings starting at $2,000
Used Cadillac DTS
45 Great Deals out of 1,584 listings starting at $2,750
Used Chevrolet Silverado 1500
2,037 Great Deals out of 158,133 listings starting at $1,995

Used Cars For Sale

2007 Mercury Grand Marquis LS Premium For Sale
3 Great Deals out of 106 listings starting at $2,500