The compressor is mounted on rubber bushings. It may be possible a bushing is damaged, and the compressor is knocking against something.

 

I think many of you CL guys are too quick to find fault in the factory air suspension. Many threads I've read; nearly everyone says, "ditch the air suspension, and convert over to coil-overs." It really isn't a hard system to maintain! My '90 ls400 has air ride, has 260,000 miles on it, and my '01 Ls430 has air ride, as well, with 118,000 miles. If you hear the air pump kick on, feel it "thump", I can almost guarantee it's the rubber bushings that bolt the pump to the car, and you can get them from any Autozone or O'Reilley's in the "help"section. They are nearly identical to factory bushings and are called "windshield wiper motor mount bushings,"and can be used all over the car where these kind of bushings are used. Seriously. I've done it on two cars now, works perfectly. The pump is supposed to run; it adjusts level/pressure as needed while driving, and think about it: If you stop at a light, keeping your foot on the brake, your car does a "nose-dive," no mater how slight, based on speed and how fast you stopped and held it there with the brakes. The height sensors detect this imbalance and air up the front. When you take off, the system will let the excess air out. I've been driving air suspension LS cars since 1996, know the system quite well. It's supposed to kick on and off the compressor. Your just noticing it because the bushings are shot, but you can get them cheap from Autozone and the like and it will eliminate the thunk/vibration! Just give it a try, they cost less than $5.

 

My compressor doesn't make a thump when it comes on, but it is fairly loud. It's a little louder than the AC system when it comes on. Is this normal?

 

In ur pic u have a white ls430 with mudguards. Where did u get ur mudguards?

 

I would be interested in replacing the bushings. Seems inexpensive and can't hurt. How do I locate the compressor? Is it easy to access? Any pictures?

 

I don't know lol I bought the car like this

 

Yes! It is normal with age. Trust me, I've owned my '90 LS400 since '96, done nearly all work myself, have factory repair manuals, and my 2001 is just now starting to exhibit the same issues. Please don't go to the expense of the dealer/repair shop before you try replacing these bushings. There are four, if I remember correctly, and you can get them from any Autozone or O'Reilley's. They fit exactly. They are in the "help" section where you find parts like window handles, door handles, ect., but they are called "windshield wiper motor bushings", and look like round, rubber bushings about two inches in diameter by about one inch thick, have a groove in the middle, all the way around (so that they fit in the sheet metal mount), with a brass sleeve through the middle. Use these to replace your old bushings..use the old hardware if you want, but use the new rubber...it'll fix the noise/vibration if your pump isn't shot: that's another issue, but I can help there, too, if necessary. I've had these cars a long time and am very familiar with all their components. Just let me know, I'll do my best to help further.

 

Hi, it's under the passenger-side, front lip, under all the plastic splash guards, and the wheel well moulting will have to come off as well. It's mounted under the front bumper on the right side (sitting inside the car), or the left side, standing in front, facing the car. I wish if taken pics of all the repairs I've done over the years, but i'm sorry, no: I do not have pics. I'd recommend using one of the parts diagrams from, say, Lexus of Atlanta, to see exactly where it mounts if you don't have a factory repair manual, like I have. Let me know if you need help