My 2004 LS430 UL, has a leaky left rear strut. Sitting over night the left rear goes down some, but after starting, the car goes back to level. This started about 2 months ago. A couple of weeks ago, we had a 6 inch snow. I started the car, and pushed the raise car button and it went up about 2 or 3 inches, just as it should. No problem backing out through the snow. I turned the lift back to normal and all was OK. I came back home, parked the car, and did not go out for 3 or 4 days. Later, I had to go out and when I got to the car, no lights or anything came on. The battery was dead. I put the charger on and left it a couple of hours and tried it again. It started right up and everything seemed ok. The next morning I went out and the battery was dead again. Again I charged the battery and all was ok once more. I checked the voltage while it was running and it shows 14.5V . So, it seems as if something is drawing current even tho everything is shut down. After checking out everything, I started thinking maybe the compressor is starting up as the leaky air strut is leaking more then it has been in the past. I can't find any info if this could be something that is normal? The battery is only 4 months old. The dealer has ordered the two new air struts for the rear and we will see if that takes care of the problem. I have read other posts on this forum of batteries going down with no known cause. If the leak is very small, one would usually not even take notice, The compressor would only run for a couple of seconds, but as the leak got worse, as mine have, it would run longer and over night, it could take the battery down. The new struts for mine will be installed next week. The we will know for sure if the compressor come on automatically. Has anyone else had this problem?

 

I posted a thread several days ago about my battery dying after just 1.5 years... Got no replies. What is interesting is that I have an ultra also, and for first time ever I hear compressor going on for a couple of minutes when I start the car sometimes. I almost never, ever heard it before, even during auto-lowering or re-raising after stopping from highway speeds, unless i flicked the ride height switch. Was thinking I might have a leaky air strut... However, I have never heard the compressor activate when the car is off, so I doubt that is the cause of our issue. If my new battery suddenly depletes I would have to reconsider. I figured an occasional compressor activation seems harmless enough for now, I hope... but I will keep an ear on it. It could also be that I am driving less frequently these days, so more chance for a small leak to matter.

BTW, 2 new air struts sounds quite pricey. I have been hoping to avoid dealing with that any time soon.... May I ask what dealer is requesting, installed? Given a 15 year old car where the overall ride quality isn't quite what it used to be, I am not sure what I would do... For all I know, other suspension components are contributing (bushings, lower control arms, etc.) but no overt symptoms, and I don't have an indy mechanic I really trust to ask. For now I am tolerating the car fine, just drove it 400 miles in 2 days on highway just fine, for first time in nearly two years.

Sorry I am not able to help, but I found your case a bit similar to mine and wanted to share.

 

You may have a slow leak in one or more strut. Mine started to go down just a bit on just one corner when I would leave it parked for a few days. That started last year. So it has been getting near the time to replace the rear pair. I checked with our local Toyota dealer here and they quoted me a price for parts and labor about $3600,. I have a Mercedes S430 that has the same suspension and the MB dealer wanted $3800 for two struts. That dealer is 150 miles from my home, so I found a local shop that always has MBs, Audi's in the shop. They are the only ones around that know what they are doing. They charged me $2125 parts and labor and I was real happy with the improvement in the ride. So I am having them do the Lexus and total cost will be $2350. The reason it is a little more than the MB is because they have to free up the rear seats to get to the upper strut mounts. There is a lot of wireing back there plus the AC stuff, so it takes a little longer. Even converting to coilovers will require the same labor time so I prefer to keep the same smooth ride it always had, so I will stick with the air struts. By the way, I called around and found Alexus dealer about 125 miles away, that's the nearest, would charge about $3850. The Toyota dealer cost less. I don't know if that is the same all over, You just have to call around. Good luck......

 

Demark1, it sounds like the compressor’s bushings may be failing. It’s a relatively cheap fix.
once they replaced the bushings the sound totally stopped and it’s been silent ever since (maybe 5 years ago).

 

It sounds like when I move the ride height switch to high... I always heard some noise then, but you may be right, it may be louder now. Who can check that? Dealer I fear is just likely so say it is fine or I need a new compressor, vs repairing... I doubt the average mechanic would know... Any additional advice appreciated. Also any idea on price? Compressor itself is around $2k from what I have read, although Arnott may make one cheaper... How much for just the bushings? Thanks...

 

I think it was about $300 at the dealer, independent would be less. My service advisor said if it was anyone else (besides him), they would’ve tried to sell me a whole new compressor! It’s been working fine on the original compressor. It’s an 04 with 191k miles now.

 

aypues: Would the compressor's bearings, if worn, cause the air shocks to leak? I just had the rear shocks changed and the new ones are doing the same thing the old ones were. They leak down within 2 days, if not driven. I picked it up fri and parked it at home. Sunday, today, I see the rear is way down. I will go back to the shop Mon and have them look for the leak. I think maybe it was not leaky shocks but a leak somewhere else.

 

No, the compressor bushings shouldn’t cause an air leak as far as I know. It might be the lines. Have they checked the system lines for any leaks?

 

They tell me there is a valve back there that is leaking. Cost to replace is about $450. It seems strange that the one left rear would go down if not driven for 4 or 5 days, but, after replacing both rears with new ones, both will go down over night. This does not sound right to me. I am waiting for a call back and a good explanation of how all of a sudden both units go down so fast.

 

Had the valve replaced and it no longer leaks. " I hate when that happens"

 

Thanks for the update. So the root cause was the VALVE SUB-ASSY, HEIGHT CONTROL, NO.2 (48096-50040).

 

I assume that was the one. It had one input where the airline connected, and two outlets, one to each rear suspension unit. There was also a 3 conductor plug on it. They did not list a part number. The price of the valve was $400. plus labor. Everything is fine now.