Hello,

It seems like my wife's 2006 RX330 does not get as cold as it used to. At times, it will even blow warm and humid air, even though it is set to max cold, although this is intermittent, which to me, creates a harder problem to diagnose.
For example, if I put the AC on Auto, at 70 degrees, it never gets cold enough for the fan to drop below the Medium fan setting. To me 70, is not that cold, and it should be able to reach this temperature, and then slow the fan down to just maintain the temperature. I can even put the system on Max AC, and it the fan blows at the High setting, but it never gets really cold.

Can anyone give me an idea of what I should look for, or tell the mechanic, so that I am not spending a ton of money on them diagnosing the problem?

Thanks

 

First, check the fluid levels for your coolant. Make sure the level for the reservoir is good. That is a simple item anyone can do.

If that is OK then you are looking at a number of different possibilities and it gets more complex from there. Could be the air mixture servos. Could be freon levels. And so on. At this point you are best served by having a competent shop take a look at your problem. A Toyota or quality independent shop if you want to avoid the costs of the Lexus dealer is a good alternative. They will have the right tools for the job.

Perform a search here in the forums for additional information that already exists on this topic.

 

I haven't dealt with the A/C issue with Lexus. But I had similiar issue with my 98 Ford Explorer. Based on the symptom you described, there are several possibilities.

1) Freon is low. If you have the A/C gauge, measure the pressure of both low and high service port. If you don't, check to see whether the compressor is enganging or if accumulator is cold. The accumulator should be very cold on touch.
2) Blend door is broken. I am not sure whether RX uses blend door or some other way to mis the hot and cold air. But this is really common for other cars/trucks.

 

Question: can you hear/feel the compressor kicking in when you turn on the AC?
If yes, then your freon is low or out...that means there's a leak somewhere in the system
If no,....rut row Raggy...$$$$$$$$$

 

You can "fix" this add freon to the system if that's the prob. But its only a bandaid

 

on most cars also usually just to the irght of the stereo, near the key location, you'll see a small inch size square with several slit holes in it. that's the cabin temperature sensor back there. over time it can get clogged with dust. get a tv dial cleaner, aerosol can, and blow air into holes. it may simply be sensor is dusty.

 

I just used a can of compressed air and blew it (carefully) in there.

 

I was not able to check the radiator reservoir last night, but can hopefully do that tonight. If, by chance the cabin temp sensor were dirty, why would that cause warm air to start flowing throught the vents after cool (not cold) air had previously been coming out? I have checked in the past when I noticed this occurence, and found that the fans were not turning by the radiator, which is normally the case when the ca is blowing cooler air out.

 

Also, make sure the AC Recirculation is ON.

 

Sounds like it`s possibly low in freon. Did you do an A/C diagnostic test on the control panel? Key off; press and hold the auto/recirc button while turning the key to the on position. That will tell you if you have any servo motor problems etc.

 

You said it was intermittent. Does it NOT blow cool air WHILE AT A STOPPED POSITION, and does it blow cool air WHILE MOVING???

I also need to know -
Does compressor kick in?
Can you switch the fan blower to and through the different modes - dash, below dash, vent, combination, etc.
Have you changed your internal vent filter?
Do your radiator fan motors kick on when the A/C is ON and CLUTCH engaged?
Can you see any freon leakage (oil) from anywhere in the lines coming from the condenser or the ac compressor?
Does the clutch STAY engaged if it is indeed turning on?
Is there condensation dripping from the car under the passenger side of the engine compartment when the clutch is engaged and running?


Answer those questions and I can probably diagnose your issue.

 

Sorry, I have been away and pretty busy with work/life.
Here are your answers as best as I know.

You said it was intermittent. Does it NOT blow cool air WHILE AT A STOPPED POSITION, and does it blow cool air WHILE MOVING???
The air is never super cold while driving, unless you have been driving for quite some time does it get cold enough in the cabin of the car. The last time I noticed the warm "humid" air coming out was when I had slowed down to about 5 mph or so after having driven for an hour or so.

I also need to know -
Does compressor kick in?
To me, it sounds like it is kicking in, and the fans are turning at the same time. S I cannot see the belt, I am not sure how to confirm that it is engaging. I have seen in the past that when the “humid” air was blowing out of the vents that the fans had stopped running….

Can you switch the fan blower to and through the different modes - dash, below dash, vent, combination, etc.
Yes, and I ran the self test on this, and it seems to blow where it should be

Have you changed your internal vent filter?
I change that every 10K or so, and the reminder has not come up yet

Do your radiator fan motors kick on when the A/C is ON and CLUTCH engaged?
The fans come on at first, but then seem to usually stop when I am having the issue. I am not sure about how to tell if the clutch is working or not

Can you see any freon leakage (oil) from anywhere in the lines coming from the condenser or the ac compressor?
I have not seen any yet, but am not sure exactly where to look, and how much can be seen as there is so much packed into this engine bay.

Does the clutch STAY engaged if it is indeed turning on?
I don’t believe it is

Is there condensation dripping from the car under the passenger side of the engine compartment when the clutch is engaged and running?
Definitely afterwards, but I will have to confirm it is dripping there while it is running

 

I would get a gauge and get a freon reading

 

Did you ever figured out what the problem was with your A/C ?