Hello, noob here.

My wife inherited a 2000 Grand Marquis from her Grandfather, it's in immaculate shape except for a couple things. The one thing that has me wondering is the A/C does not seem to get cold. There was a receipt in the car for service this past August where it says they filled the A/C system.

Here's what I noticed...

If the car is running at idle, everything works fine. With the heat, hot or cold vented air etc, everything runs fine. However, when we turn on the A/C or either hot or cold defrost, there is a spinning sound that starts and repeats itself every 3 seconds.

I checked the belt assembly, and the A/C Clutch Plate (the three bolted dealie on the front of the A/C compressor shown below is where the spinning sound is coming from...

[img]uploads/Mechamaniac/671A4_84872208.gif[/img]

When this happens, the serpentine tensioner arm moves forward a couple of inches as well, no doubt providing extra tension on the clutch assembly so that it can spin the compressor. The clutch plate spins rapidly for about 1 second, then stops, after 3 seconds, it does it again and keeps doing this as long as we have either the AC or the Defroster on.

I'm guessing that I need a new A/C Compressor, but I'm not sure. Has anyone here experienced this problem, and is it common to the Grand Marquis? Any idea how much it would cost to get it fixed?

Thanks!

Edited by: Mechamaniac

Failure of the A/C compressor is not anoverlycommon problem. The A/C clutch is designed to cycle on and off during normal operation, however, it's not supposed to cycle as fast as you describe.


There a couple of things that I'm aware of that might cause your A/C to cut-off in the way you describe.


- A/C pressure switch: if this switch is bad your compressor will not come on or will come on and immediately turn off. For a test you can disconnect the switch and short the pins together with a wire to see of the compressor comes on and stays on as it should. If it does, replace the switch. DO NOT drive around with the terminals shorted. As stated above, the compressor is designed to cycle on/off during normal operation. With this connected shorted it wont' do that and it will damage the system if you operate it too long in that fashion.


- Failure of the electric fan wiring connector on 98-00 models is somewhat common. To test,start up the car andturn on the A/C to MAX A/C, and the fan on high; all the way on cold. Pop the hood, and look at the electric fan. If it isn't spinning, there is a problem with the fan and/or it's circuitry.

Thanks!

As it turned out, the system will also cycle this way if the freon is low. Her grandfather never used the AC so he would never have noticed this problem. I topped off the R134 and the problem stopped. The only thing I have to see now is if it starts again. Hopefully there isn't a leak, but it's at least good to know that the clutch and the compressor are working correctly.