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Discussion Starter #1
So my A/C has been working intermittently over the past 2 years. Ive tried stop leak and ive recharged the system. This year i decided to actually solve the problem.
Ive tried reading through the forums and havent found someone with the same problem as me so i thought id bring it up.

Attempt #1 this year:
i had it vaccumed 3 times just to try to clear up any clogs that might be there and then filled it with freon and it would blow cold at highway speeds for a few days and stopped. (Low side around 90 and high side around 200)
Attempt #2:
Changed the expansion valve and filled it. AC worked at idle but once i started driving the low side pressure went high and stopped blowing cold. (Didnt check pressure before but after it went warm low pressure was 90 and high side was 180)
Attempt #3:
Changed the condenser which came with the new drier and another new expansion valve. I had the system vacuumed for a half hr and filled. Once again blew cold at idle. But got warm once i started driving (low side PSI 30 high side 190)
Attempt #4:
Found the lexus service manual online on how to properly fill the system so i drained the system and filled it while holding the rpms at 1500 ect. Drove the car for almost an hour(at night) and the AC was blowing cold the whole time but the next day it was blowing warm. (Low side PSI 25)
5th attempt:
5th attempt is asking the forum for help....help

Ps both fans work and the ac clutch does engage.
Ive read some where that the car has 3 different temperature sensors (ambient, room, and solar) that all work with the AC system and if those go bad then it'll mess with the ac temps
My best guess is that its the compressor or those sensors.
 

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2002 Lexus IS300
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ac compressor is bad. Have the shop hook the gauges back up to it and run the car with the ac on. If the pressures don’t drop or even move (the case of my car) when the ac clutch engages, your compressor is bad.

my car was doing the same thing. Colder while driving at freeway speeds. Would intermittently be cold at idle. The ac clutch would ALWAYS engage and fans came on like they should have but when I hooked it up to my ac machine, the problem revealed itself by way of a bad ac compressor EVEN THOUGH it does engage and disengage correctly.
 

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Discussion Starter #5
ac compressor is bad. Have the shop hook the gauges back up to it and run the car with the ac on. If the pressures don’t drop or even move (the case of my car) when the ac clutch engages, your compressor is bad.

my car was doing the same thing. Colder while driving at freeway speeds. Would intermittently be cold at idle. The ac clutch would ALWAYS engage and fans came on like they should have but when I hooked it up to my ac machine, the problem revealed itself by way of a bad ac compressor EVEN THOUGH it does engage and disengage correctly.
I was hoping it wasnt the compressor. Did you change yours yourself? Seems like a pain in the ass. Especially doing it at home.
 

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2002 Lexus IS300
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I was hoping it wasnt the compressor. Did you change yours yourself? Seems like a pain in the ass. Especially doing it at home.
I did change mine myself. It’s really not that bad. I also bought my compressor from Amazon. OE denso unit cost me $300
 

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2002 Lexus IS300
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I know the ps pump has to be moved aside to the compressor out but did you need to take the rad out?
No radiator can stay. P/S pump needs to be moved along with it’s bracket. The. The rest can be done from the thé bottom. It’s really not that bad. Would probably take a hour and a half.
 

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Mr. Roo
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Sounds like you're in the same boat as me. I'm actually surprised you have replaced everything except the compressor, and even after everything you've changed, it's the compressor you're worried about. IMO, for me, it's the expansion valve that seems like all the trouble! That's the only part left on mine to replace to try to get mine working, but I even had the dash out and wasn't willing to try and figure out how to replace it.

I have, however, replaced the compressor twice (and yes I took out the radiator). I also bought a Denso unit from Amazon, but it came with a bad sensor/switch (the wires fell off when charging, found that out the hard way, had to replace it again). It's nothing really that bad, just a lot of work doing things one bolt at a time.

Some posts of when I went through it:

 

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Discussion Starter #12
Sounds like you're in the same boat as me. I'm actually surprised you have replaced everything except the compressor, and even after everything you've changed, it's the compressor you're worried about. IMO, for me, it's the expansion valve that seems like all the trouble! That's the only part left on mine to replace to try to get mine working, but I even had the dash out and wasn't willing to try and figure out how to replace it.

I have, however, replaced the compressor twice (and yes I took out the radiator). I also bought a Denso unit from Amazon, but it came with a bad sensor/switch (the wires fell off when charging, found that out the hard way, had to replace it again). It's nothing really that bad, just a lot of work doing things one bolt at a time.

Some posts of when I went through it:

The expansion valve wasnt bad and you dont need to take any part of the dash out. Its above the gas pedal under some insulation. A good razor and you can cut that stuff and pull it back and then its just 2 torx t25 i believe and pry the hoses back a little and the expansion valve falls right out
 

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Sounds a lot easier than the wife's rolla, the expansion valve on that was at the top of the dash and needed the fan unit removed to access it. Wasn't what i would call difficult but it took a lot of time to pull everything apart and put it all back together.
 

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Mr. Roo
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The expansion valve wasnt bad and you dont need to take any part of the dash out. Its above the gas pedal under some insulation. A good razor and you can cut that stuff and pull it back and then its just 2 torx t25 i believe and pry the hoses back a little and the expansion valve falls right out
Wow really? Everything I read said it was in the dash and had to remove it all and then the support bars and stuff. Your way sure sounds a lot easier LOL
 

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Discussion Starter #16
Hmm, the write up is a LOT shorter than the rolla was :sneaky:

View attachment 135363

Check out this video, If its anything like the GS then looks like its simple as! :oops:
Its basically exactly like the video above but if im not mistaken the is300 has a little more room than the GS in that video but its basically a foot above the gas pedal

Took me about an hour to do
 

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Discussion Starter #18
So far the ac is working after changing the compressor.
Heads up for anyone that reads this in the future. GPD makes a kit with the compressor, condenser, expansion valve and o-rings for like $300 but the expansion valve doesnt fit right. The rest works
 

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2002 Lexus IS300
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Good to hear it’s working! Thanks for keeping us updated.
 
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