QuestionQUESTION: Mr. Spinks,
I bought a 2004 ford crown vic LX Sport in october 2010, and since I bought it there has been a noise that comes from the front of the car. I took some time and figured out that every time that the air compressor kicks on, this noise occurs. It will only do it once or twice a day. It will pick the back of the car up when it kicks on. I noticed that the front bolt that holds the air box down, which also helps to hold the corner of the plastic inner fender down had rusted out. I replaced the bolt and thought that this would stop the noise but it didn't.
I am thinking that it might be the drier that is making the noise, but not sure. The main reason I say this is because the compressor is working by pumping the back of the car up, and the drier is quite rusty, mostly the part of it closest to the center of the car. It seems like only surface rust, but I just took a quick glance. Everything was pluged in, the air hose and the two electrical connections. (which looked good, no corrosion)
If this helps, I drive about 60 miles per day, most of which is highway. The car has 123,640 miles on it.
If you need any more info, don't hesitate to ask.
Thanks,
Charles
ANSWER: Charles,
The air suspension compressor should come on every time the car is started or weight is added. It also will "vent"......which sounds like a purge of air when the ignition is turned off and the door is closed. What makes me wonder if you have an actual air suspension problem, is because you said the "dryer" had surface rust. All Ford/Lincoln dryers are made of plastic....which of course doesn't rust. It may get dirty and look rusty....but you know what I mean. Also, you said it has 2 connectors. All these compressors have a single 4 pin connector and a single air line. After chewing on this for a few minutes, I'm wondering if your looking at the ABS(antilock brake system) Hydraulic Motor.
When do hear the noise? Is it when the car is started?..... after you reach approx 20 mph?......or sometimes when you braking?
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QUESTION: Mr Spinks,
Is the ABS motor underneath the air box? I could have been thinking of something else when I wrote that. When I put about 100 lbs of steal in the trunk at work, it kicked on right after start up, which happens when there is weight added to the car.
I have only heard the noise mostly after start up, but occaisionally on the highway (approx. 70 mph) I can feel the floor vibrate. Only once did I feel/hear it while braking and that was coming to a stop sign. In that case, it was already making the noise before I touched the brakes.
Although once, it did make the noise right before I shut it off, and it continued for about 5 seconds after I pulled the key out of the ignition.
The ABS seems to do its job well considering I have driven it through the snow a few times without hearing the noise.
My 2004 workshop manual states that the hydraulic control unit is mounted to the frame rail. Is this true? I actually put my hand on the top of this unit while the noise was present, and didn't feel this unit even vibrate. This is what I speculated before I found out where the air compressor was which was within inches. The part that is making the noise is torwards the fender, inside the inner fender well(where the air compressor is located).
I could have seen the dirt, and thought that it was rust like you said. It is easy to overlook sometimes.
I don't have any lights on my dash lit up, which is why I am so confused.
I don't think in this case it will help, but I have a nice code reader for the OBD2, and if you want I could give it a shot. Whithout a light though, I don't think it will drag anything up.
The noise sounds more like a large air compressor that I have in the garage. Its not as loud as one in the garage though. Are they supposed to make that type of noise.
Would the ABS motor make a noise without applying the brakes?
I hope this helped,
Thanks again,
Charles
AnswerCharles, OK, good. At least I know we're on the same page. Yeah, I think the noise your talking about is the air suspension compressor(on yours=under the air filter assembly). It having to come on while driving means that you have a leak in the air springs. Keep in mind that it may have had a leak for quite awhile, but as long as its able to pump up to normal height "within 90 seconds", it thinks everything is ok.....even though thats 3 times too long!
With all that being said, the air springs need replacing and seeing that the compressor is getting loud, most likely it'll need replacing in the near future. Your first goal is to first make sure your up to the cost of keeping the air suspension. You can get the air compressor for about $150 and the air springs for another $168. Another option is to do the coil spring conversion. At $168, your done with the air suspension completely. Either way you wind up going, the best place to get your parts is www.americanairsuspension.com
