ShannonT

Hi Everyone,

I have successfully researched many things on this forum, so I owe many thanks to all the knowledgeable members.

I'm new to posting, so please forgive the formatting.

Here is the situation:

My AC no longer blows cold.... It only blows cool.

Examples with Max Cold AND Recirculating Air:
Ambient Air Temp Temp coming out of center air vents
75 Degrees 60 Degrees
85 Degrees 63 Degrees
89 Degrees 70 Degrees

I had the R134a vacuumed and leak checked. It was at 10oz, where capacity is 17.6oz, so they charged it back up, but the issue remains the same.

My mechanic has checked the condenser and it shows consistent temperature all over it, so he believes there is no issue with the Condenser. He did, however, indicate there may be an issue with the (1) The Compressor or (2) The desiccant element could be clogged with debris, or enlarged from absorbing moisture in the system, causing blockage to the flow of the R134a.

Primary reasons for this conclusion:

• Line out of compressor is cold (He said it should be colder than it was. I don't recall the temp), up to the point where it enters the dryer (with the desiccant element), just before entering the condenser.
• The condenser temp was consistently ~170 degrees across all areas checked.

His Recommended Actions:

1. He is suggesting we replace the compressor first, as he believes it to be the primary cause, based on the temp coming out of it.
2. If not fixed, he suggests replacing the Dessicant Element. Since the condenser has a consistent temp, he doesn't believe it has any blockage.
3. If not fixed, he suggests replacing the expansion valve, as debris could be blocking flow at that junction.

It feels like he is being honest, as he is suggesting the least labor cost first, then escalating based on labor costs to repair.

I'm looking for some confirmation to his recommended path to resolution.

SECOND QUESTION:

Since debris in the line either comes from the compressor or a burst dessicant element, any thoughts on adding in-line filters before the dessicant element and after the condenser? Would this minimize any future contamination in the system? If yes, any suggestion as to which brand and which filter to use?

Thanks for all the help!

Shannon T.

ibidu1

iTrader: (1)

I think this mechanic is trying to swindle you, 14 hours for labour on ac system. What was his reason for vacuuming the original freon? Very rarely do you hear an ac compressor going bad on a 3GS.

I just feel like he didnt fill the freon to the proper level for you. Or may have added too much!

For an ac not blowing cold air the first things I would do is replace the cabin filter with an oem or denso brand. Next I would grab a water hose and the space between the condenser and the radiator. That area is prone to collecting dirt/mud/dust/debris etc. Make sure you can clearly shine a light through both the radiator and the condenser.

Lastly I would go to walmart and buy one of those small cans of freon with the gauge on it. You can pick one of those turkey thermometers to where you can just drop it inside the vents so you can monitor the temps. Start the car in a hot day "because you can fill freon on a cold day" hook up the can on the LOW side ac port. The gauge will tell you where the freon level is at, if it is too low simply spray a small shot, then wait a min or two and check the thermometer to see if the temps dropped. Do this until you see about 35 to 50f degrees

If you plugged the ac freon in and see the freon on the high side, simply turn off the car, and bleed some out of the ac port. Adding too much freon can damage the compressor, and not give you enough cooling. Too low and the compressor will not get triggered on and the ac temp will be low aswell. You want to find that sweet spot. Goodluck! Its super easy to test for yourself!

MX73

The compressor jobs is to "pump" the freon. Just like a water pump. It's also a very expensive job and that's the first thing I would not replace. Too much freon has an opposite effect and doesn't allow for proper heat exchange.

First off, I would follow ibidu1 advice and check the cabin filter.

Second off, I would check the fans. There is the main fan and secondary fan that comes on under load, ie when the compressor kicks in. Make sure those fans are functioning because it is responsible for "pulling" the heat out of the condenser. Also, make sure the condenser fins are straight and free from debris.

3rd, get a 2nd opinion from someone else.

silverlake

I agree I’ve had it happen on my Camry to much Freon can make it not perform correctly sometimes all you need to do is purge the line can you hear the compressor kick on ?

ShannonT

Thanks for the tips.

Here is where I stand. (Images below)

• Cabin Filter Replaced
• R134a Level shows about 42psi (In the middle of the Green) on the low side (up by Brake Booster, with 'LO' on the cap).
• Condenser shows light, but thoroughly sprayed out anyway.
• Both fans are engaged and turning.
• No change in Temp at center vent.

It's 81 outside and AC is blowing at ~72 degrees.

Also, going to an alternate mechanic tomorrow.

Any other thoughts?


Right in the middle of the green

Outside is 81, blowing about 72

Engine Temp is normal

ibidu1

iTrader: (1)

Good sometimes when an ac compressor is bad the gauge will peg out. Did you make sure the ac compressor clutch is click on and off?

I would add more freon

ShannonT

Yes, the compressor cycles on and off.

To what level should I add freon? 50psi?

ibidu1

iTrader: (1)

Go up to 50, if you dont have cold ac. im thinking maybe the expansion valve on the firewall could be not working properly. Expansion valves controls the flow of freon to the evaporator inside the car.

ShannonT

Still not cold.... Ibidu1.... I have a new replacement Denso expansion valve. Any idea on labor? How many hours?

Just to confirm, you would start with the expansion valve first. Correct?

ibidu1

iTrader: (1)

Should be easy to access as it should sit on the firewall. You can swap it out yourself, make sure to install new o-rings if your valve didnt come with any. You just have to becareful when you push the metal tube/hose with the o-ring, you will want to put a small dab of lube so it slides in without tearing. You will need to release the freon, before you remove the valve. Once you finish simply recharge the freon

ShannonT

HI Ibidu1 - I found this on the Lexus website and confirmed in my engine bay... see photo below:





It looks like the Expansion valve is adjacent to the evaporater, on the inside of the firewall, behind the instrument cluster.

This is likely beyond my abilities.

If I go this route, I will go ahead and replace the evaporater, since everything will already be out.

Thoughts?

ibidu1

iTrader: (1)

This is for an older GS, but I wonder if its the same as getting access to the back of it.

MX73

If you do tackle this on your own, you'll need a vacuum pump to remove all the air and moisture that is introduced into the system.

ibidu1

iTrader: (1)

He can still do a swap of the valve, fill the freon without vacuuming at home. I have done this many times to cars with success.

If he does figure out his issue and the ac blows cold, then if he wanted can pay to have the system vacuumed, and a new drier then filled at a mechanic the correct way.

ShannonT

Thanks for the help. Will let you know how it progresses.