I noticed while waiting for my friend outside his house for about 20 minutes that the AC was not as crisp. Yes it said 106 F outside but still. Lowering the setting to MAX cold and fan in the middle it got better.
All goes back to normal once you start moving again.

I am wondering perhaps its a bit low on freon.
Can I add a can, like the ones they sell in stores? Where is the low pressure nozzle? I am afraid of overfilling it, so I am gonna do a small can.

Pointers?


Thanks

 

get the can with the gauge on it. The low pressure cap ha an "L" on it. Usually if you have to add freon, you have a leak starting somewhere.

 

Doubt its a leak, just maybe a bit low after 6 years of usage??

Also can with a gauge, know the PSI I should stop at?

Im gonna get the temp gauge and measure the AC temp, I think its supposed to be 40-50F out of vent.

 

the can with the gauge has a safe area of pressure colored green. Just stay in the green

 

Also, Freon doesn't disappear through usage, that is why I mentioned something might be leaking.

 

Thanks. I will check tomorrow the temp of AC output.

Are you saying freon never gets used up?

Also everything is fine once we are moving, and all is great in temps 100 and below. I just drove to Boston and back to NYC with no problems.

 

yes That is what I'm saying. Freon never gets used up.

 

The low port is located under the brake master cylinder.

 

Everything is back to normal. Checked the TEMP coming out of vents and it was at 40-45F.

I guess it was a very hot day.

 

I'd just love to add you are RIGHT on the money with this instinct, I'd love to know the PSI to stop at, I don't care for the yellow/red/green gauge, because all that shows is color, I'm pretty darn sure all A/C systems have an optimal pressure range vs color range .

 

Plain and simple, the hotter it is outside, the harder it is for the AC system to cool the air. It's just common sense.

A quick and dirty way to check is look for the sight glass usually on the high-side of the system. I don't have a 3GS anymore so I can't tell you where it is exactly. If you see bubbling in the sight glass, then your system could use some service.

 

Anyhow...so 100F+ today. And again, on HI and MAX COLD idling car blows 55-60F outside the vents. If I put it to Medium, it gets down to 50, and once I start driving it gets between 45-50. Which is not as cold as it should be.

When temps outside are 80-95, all is well. But not in 100+ weather.
So I added a bit of freon and I think it got a little better, but I am afraid to over fill it. Will take it to my shop tomorrow to test the system. I hate going to shops.
Id drop it off at a Lexus dealer buy they will charge me and arm and a leg, and will probably suggest changing everything from compressor to condenser to, sunroof to navigation unit, while they are at it.

Will report back tomorrow.

A bit ashamed, I thought I would never have a single problem with my Lexus. My LS400 had a killer AC.