GX 470 2003-2009 Height Control Air Dryer 4895060020 (1 Viewer)

[Tinggi]

Reviewing various posts about the rear air suspension on the GX470 I see little discussed about the Air Dryer! Looking at the service schedule I was unable to find any comments there.

Based on what I have read it contains a desiccant to remove moisture from the air before the compressor pumps it into the Air Shocks!

My question: Does the desiccant not become water-saturated after time? Is this part something that should be replaced after time?

Just curious.

 

[VoodooFarm]

This is actually an interesting question, I'm surprised I haven't ever seen it asked before but I'm assuming since most people get rid of the air ride it's never been something that comes up, and if it has caused problems it might have shown other symptoms like a dying compressor which again most people would just swap to springs, and never realize it may be an issue with the desiccant.

It definitely isn't in any service schedules, and checking the Lexus Drivers site on a lot of GX's has never returned any entries that involve it, so I'm assuming it isn't considered a serviceable item. I wonder if the dryer itself is a replaceable part, or if it's considered part of a larger system.

Searching the Repair Manual for "Desiccant" and other variations of the spelling doesn't return any results, so if the repair manual doesn't even mention it I'm not sure where we could find more info on it. The manual does mention the Dryer itself though, here's a quick diagram in case you haven't seen it. Which it does look like it probably isn't meant to be removed/serviceable on its own, but I could be totally wrong.

 

[VoodooFarm]

Posting this in a separate reply since the pages are kind of big images. But here's a closer look at the system. I'm not sure how the desiccant and dryer and filter all play into each other, but there are torque specs for removal of them if needed. I'm not seeing any diagrams of the interior of the dryer or filter though, which again makes me think Lexus probably doesn't want techs cracking them open and just replacing the unit itself.

 

[VoodooFarm]

And reading more there is actually a guide to replacing the dryer assembly. And I read further ahead to make sure I would get anything else in this post, hopefully all of this is helpful info and I'm not spamming the thread too much. But the assembly itself can be replaced, so it's not part of a larger system that needs to be replaced all together. But there's no mention of doing anything inside of the dryer assembly or the filter with any sort of desiccant, only replacing them entirely. That's all I can find right now unless you have other search terms that I could look in the repair manual for. As of right now though it seems like the desiccant itself isn't something Lexus planned on being serviced, just the entire dryer. But again I might be totally missing the mark and there might be someone more knowledgeable out there about this.

 

[Tinggi]

Like you, when I found out there was a air dryer plumbed in to the compressor, I was surprised there was literally nothing written about it.
A master toyota mechanic I know could not add anything other then it was a replaceable part! After that nothing to refer to in the service schedule as to when.

1. Toyota put it there for a reason. To remove moisture from the air being compressed by the compressor before it enters the air lines and air shocks.
2. My experience with dessicants is they eventually saturate and stop pulling moisture from the air. Toyota obviously does not see this as being an issue.

For me, I plan on replacing existing air springs in near future. I will spend the $125.00 or what ever for a new dryer at the same time.

Thanks for the documentation from the manuals.

 

[SBANGLICO]

Sample of one, but when I pulled out my air ride system the compressor/dryer was full of water. The system was still functional though, so not sure if there is a purge cycle to it.

 

[VoodooFarm]

Like you, when I found out there was a air dryer plumbed in to the compressor, I was surprised there was literally nothing written about it.
A master toyota mechanic I know could not add anything other then it was a replaceable part! After that nothing to refer to in the service schedule as to when.

1. Toyota put it there for a reason. To remove moisture from the air being compressed by the compressor before it enters the air lines and air shocks.
2. My experience with dessicants is they eventually saturate and stop pulling moisture from the air. Toyota obviously does not see this as being an issue.

For me, I plan on replacing existing air springs in near future. I will spend the $125.00 or what ever for a new dryer at the same time.

Thanks for the documentation from the manuals.

When you replace, I would recommend Arnott's. They lock into the bottom perch unlike the OEM and most of the cheaper Amazon replacements. They also seem to be the highest quality out of the non OEM options.

Here's a good thread to read through if you haven't seen it, lots of good info on replacing them. This thread.

If you replace the dryer and have the chance, it would be awesome if you could take some pictures and document the replacement for a post in this thread or a new thread. And maybe keep the old one around to crack it open and see what's going on in there, it would be nice to get some pictures of how it looks inside and what the state of the desiccant is.

Good luck!

 

[Tinggi]

Very interesting comment about the dryer being full of water! Supports my comments that desiccants have a finite life span! THEY WILL SATURATE with water!

How does this impact the compressor? Maybe, not but sure, makes me wonder.

As it goes I was planning on using Arnott Air Springs as you recommended. When I do I will change out dryer and inspect it to see if it too is wet inside!

Circumstances preclude me working on this till December the earliest! I will be sure to take phots and add to conversation.

 

[Tinggi]

I have looked at other vehicles using air suspension and they comment that when the desiccant gets wet the moist air can mess up the compressor, freeze in cold weather and impact the performance of the suspension.

Food for thought!