LS430 Air Conditioning not working?

MAN842 · June 25, 2023

Hello everyone!

I have brought a Lexus LS430 with around 150,000 miles a few months ago. As the weather was very cold back in my initial ownership, I thought the AC was functioning, but as I am currently getting baked driving around in this heatwave, it clearly isn't.

I have written down what I have done with this car in the following wall of text, so that it may help narrow down to the potential problem:

When I press the AC button, I can hear an audible drop of RPM from the engine, as if to show the compressor is functioning.

I went to KWIKFIT for a re-gas. The machine showed that it passed the leak test and was charged with around 900g of refrigerant. Still did not work. Whilst looking through the past service of the car, I found out that the car had its rear AC pipes capped off and filled with 700g of refrigerant. I took it back to KWIKFIT to drop the refrigerant to 650g; the AC still did not blow cold.

I took the drivebelt off and moved the AC compressor pulley, which was moving very freely without any sounds/resistance. I ran the onboard AC diagnostic test and received the only code of "00", which means no fault?

I recently had the "Change A/C Filter" code on the dash, way before noticing the AC not working. I took out the filter and reset the code to see if AC would work, but no luck.

I did the timing belt and water pump change myself on this car as soon as I brought it. During the works, I did have to loosen the bolts holding the AC compressor and move it slightly out of the way. Could I have pinched a line or whatnot?

I have taken the car to an AC specialist. He mentioned that it seemed the magnetic clutch was stuck on, therefore needing a new compressor. But after research, I find out that the LS430 AC Compressor does not have a magnetic clutch; it is a direct drive type. It seems he misdiagnosed the problem, which making me fairly hesitant on moving forth with what he said, as I don't want to ball out major ££££ to make a repair that does not fix the issue. I have visited further garages for second opinions and have been met with inconsistent thoughts.

I am quite stuck with this issue.

I thought it could be a common issue with the LS430, which can be solved easily. Is there anyone who experienced a similar story with my car? I am quite a handy person, so if there are a couple certain things the problem could be, I may be able to fix it myself. I just need some guidance.

Also, is there anyone that can recommend me an AC specialist that has some experience with the LS430 models? I live in Potters Bar and would commute quite a remarkable distance to have a solid diagnosis :D.

cruisermark · June 25, 2023

I can't help with your query - but I seem to remember someone having a similar problem and the fault was with the compressor/clutch etc

If you get stuck these guys are well recommended on the forum

Car Garage Watford – MOT, Service, Repair | Japex

Malc1 · June 25, 2023

Mert hi and welcome to the LOC . sorry you've hit upon a snag . might be lucky and someone here with a Ls430 might be able to help !

What's the regn by the way . is it a first or 2nd generation Ls430 ?

I have no discernible advice to offer sadly

Good Luck with it all

Mine on the Ls400 stopped working about a month after I bought her some 12 years back . reading the issues with re-charging and replacing it all I just decided to open windows at the appropriate times 😥 . the cost even then of fixing it seemed disproportionate to the price I paid for the car ..... £1400 ....and I've now doubled the mileage to 246k miles too ✌️ wot wondrous cars these are eh !

Malc

MAN842 · June 25, 2023

Hey Malcolm, thank you for your kind words.

It's a 2nd gen LS430.

I have to wind the windows down aswell :D.

I may need to go abroad with the car, which is why I kinda wanna fix the AC, if I can, ASAP.

If not, my family will be in for a nice ride of 40°C air slamming into their faces at 80mph 🙂.

MAN842 · June 25, 2023

11 minutes ago, cruisermark said:

I can't help with your query - but I seem to remember someone having a similar problem and the fault was with the compressor/clutch etc

If you get stuck these guys are well recommended on the forum

Car Garage Watford – MOT, Service, Repair | Japex

Thank you Mark!

I will call them up and arrange a diagnosis ASAP

Howplum · June 25, 2023

This company might be worth a try:

http://www.jttautotech.co.uk/air-con/

It looks like a comprehensive service they offer for £75.

steve2006 · June 25, 2023

Have you checked the condenser? Being mounted at the front they are fully exposed to debris, also when the car is idling with the AC switched on do you hear the cooling fan kick in and out?
Other items to check are the external air temperature sensor and internal cabin temperature sensor, the latter can get clogged up with carpet fluff giving false readings to the climate control ECU.

Tulpen · June 25, 2023

I had the same problem during my 15 years of LS 400 ownership. When I switched the AC 'ON' there was a discernible drop in engine RPM but no AC operation. It turned to be a compressor fault and I had it replaced. It was the only expensive problem I had with the car in all those years. Unlike Malc, I think that AC is essential......and why would you drive an LS with the windows open, when one of the joys of owning one is the complete silence as you waft along the highway!

Malc1 · June 25, 2023

23 minutes ago, Tulpen said:

is the complete silence as you waft along the highway

hahahahaha. drowns out the utter " complete non silence " of 'er indoors jabbering away sometimes !

Malc

runsgrateasanut · June 25, 2023

The revs increase when the compressor engages which is why they say the Car uses more petrol when A/C working. I just reported that my Car A/C was reharged and goes down to 9.2 degrees. If and when I drive to France it will be essential to keeping me safe. An old boy with too much heat has a tendency to fall asleep !

MAN842 · June 25, 2023

4 hours ago, Howplum said:

This company might be worth a try:

http://www.jttautotech.co.uk/air-con/

It looks like a comprehensive service they offer for £75.

I shall look into them too. Thank you for the link, Howard 🙂

MAN842 · June 25, 2023

3 hours ago, steve2006 said:

Have you checked the condenser? Being mounted at the front they are fully exposed to debris, also when the car is idling with the AC switched on do you hear the cooling fan kick in and out?
Other items to check are the external air temperature sensor and internal cabin temperature sensor, the latter can get clogged up with carpet fluff giving false readings to the climate control ECU.

Yes I have checked the condenser. It was looking fine. I still gave it a wash just in case.

With regards to the two sensors, I think if I put the AC settings to MAX COLD, it should bypass the sensor readings and give maximum cooling? (btw AC still does not work at MAX COLD) so I think they're not an issue?

MAN842 · June 25, 2023

1 hour ago, Tulpen said:

I had the same problem during my 15 years of LS 400 ownership. When I switched the AC 'ON' there was a discernible drop in engine RPM but no AC operation. It turned to be a compressor fault and I had it replaced. It was the only expensive problem I had with the car in all those years. Unlike Malc, I think that AC is essential......and why would you drive an LS with the windows open, when one of the joys of owning one is the complete silence as you waft along the highway!

yeah it does seem like mine could be a compressor fault aswell :,) I'm still going to contact one of the garages recommended here; I may be in luck and have something like a pressure switch sensor fault XD

steve2006 · June 25, 2023

It may have been damaged when the rear pipes burst and it lost the refrigerant if it was left empty too long maybe.

jamesbradbury · January 4

Did you get anywhere with this? I have a similar issue I'd like to sort before summer! Cheers

MAN842 · January 5

Hey James,

Nope, I've had to leave it as I am quite busy with work 😞.

I should start looking back into it before summer too.

I did some reading and found out that when the AC system runs low on gas, it is detrimental to the AC compressor on these 2004-2006 LS430's. They are a direct drive system so they're sort of constantly on. When the gas leaks, something-something lack of lubrication something-something compressor kaboom 😀. My rear AC pipes have been blocked off just before I brought the car. I am assuming that it had a major gas leak that may have knackered my compressor.

I look for used AC compressor in the UK that works (for the 2004-2006 model as they're unique) so I can scratch it off the list, and it seems I would have a higher chance of being struck by thunder as they seem to be the first part to be stripped from a breaking car XD.

So James, my advice is, if your rear AC is capped off recently, it may indicate your AC compressor is knackered. Hopefully someone on this forum can confirm if this hypothesis makes sense or is bs.

Razor61 · January 5

On 6/25/2023 at 1:57 PM, MAN842 said:

But after research, I find out that the LS430 AC Compressor does not have a magnetic clutch; it is a direct drive type.

Where did you get the info that it's a direct drive compressor and doesn't have a clutch? Just curious because from what I can see it does have a magnetic clutch and isn't massively different to the LS400. From looking on Amayama and RockAuto there is a magnet clutch assy on the front which looks the same as the LS400, which definitely does have a magnetic clutch.
My previous LS400 had an AC issue and it was the clutch on the compressor so bought a Denso one from RockAuto, ordered Friday lunchtime and it was delivered Monday afternoon!!
They are listed on RockAuto for your car, Denso 4710574 - £470 including carriage and duty, and it looks like it has a clutch assy to me.
You should be able to check yourself, just have a look at the compressor and if it has a clutch assy it will look like the pic of the one listed on RockAuto and Amayama.

RockAuto link: More Information for DENSO 4711574 (rockauto.com)
EPC link: Heating & air conditioning - compressor for Lexus LS430 UCF30R - Auto parts (epc-data.com)

Razor61 · January 5

I've not heard of a car 'direct drive' AC Compressor but maybe someone knows about this and can enlighten me.
Direct drive and belt drive types for air compressors for workshop use etc...................yes but not direct drive on a car.
I'm not an expert but afaik direct drive is where the 'motor' is connected direct to the compressor and belt drive is the where the 'motor' drives the compressor using/via a belt ( same as a car )

MAN842 · January 21

On 1/5/2024 at 10:10 AM, Razor61 said:

I've not heard of a car 'direct drive' AC Compressor but maybe someone knows about this and can enlighten me.
Direct drive and belt drive types for air compressors for workshop use etc...................yes but not direct drive on a car.
I'm not an expert but afaik direct drive is where the 'motor' is connected direct to the compressor and belt drive is the where the 'motor' drives the compressor using/via a belt ( same as a car )

Hello Razor,

Sorry for the late reply; here's a link of a video of a 3UZ specialist in New Zealand, speaking about the AC system of the 2004-2006 models.

Razor61 · January 22

12 hours ago, MAN842 said:

Hello Razor,

Sorry for the late reply; here's a link of a video of a 3UZ specialist in New Zealand, speaking about the AC system of the 2004-2006 models.

Nice one, thanks for sharing it. You learn something new everyday, so the compressor is 'turning' constantly and I suppose the solenoid controls whether it's 'engaged' or 'conditioning'.
Lots of info on his channel, i.e. a link to a workshop manual site which will be useful to a lot of people without one - https://charm.li/

Ash Knight · August 1

Hey did this get sorted? The AC on my GS430 stopped working a couple weeks ago and it's been DIAR in this crazy heat we've been having!

I had a garage check mine over as I'm not as "hands on" as you, and they diagnosed a compressor fault but didn't seem too confident. There doesn't seem to be any leaks, but I think the car was being driven with no AC gas for quite a while, which could've knackered the compressor. I bought the car in December and the AC wasn't working then, so I had it re-gassed in May and it worked perfectly until recently, when it suddenly stopped blowing cold. Leak test done and doesn't appear to be any leaks, so I'm stumped!

BigBoomer · August 15

Mine died years ago and after getting a quote for nearly 2k (Compressor, condenser, dryer, sensor and some hoses) I decided I could live without it.
The compressors on these are not the best and seem to crap out after 20 or so years.
The fault is almost always in the control electrics/electronics in the compressor itself. Probably another instance of the lead-free solder cracking.

NemesisUK · August 15

2 minutes ago, BigBoomer said:

The compressors on these are not the best and seem to crap out after 20 or so years.

Only lasts 20yrs! That's scandalous! 😳😁

Malc1 · August 15

I mentioned earlier that my 95 car A/C was kaput shortly after purchase ( in 2011 ) and it's still so ............ still doesn't bother me at all tbh

BUT

my 91 Ls400 ( bought last year 👍 ) has amazingly brilliant aircon and I don't think it's ever been checked out ..... no discernible bill for it anyway .... I do leave it on constant tho' so that might be the answer to potential longevity 🤞

Malc