My wife's 2007 wasn't cooling very well. I put a guage on it and it was slightly low so I added a can of R134. Cooled better for a (very) short time. Now it doesn't cool at all. Any ideas?

 

Perhaps it needs to be serviced by AC professional.

 

Probably does. For the heck of it I released some of the refrigerant. AC now working. Suspect that I over filled it. Is there a high pressure shut off or something of the sort?

 

[QUOTE=sapeluso;9503816]Probably does. For the heck of it I released some of the refrigerant. AC now working. Suspect that I over filled it. Is there a high pressure shut off or something of the sort?[/QUOTgauge mouted on it. E]

If you bought the refill freon at an auto store I assume it had a gauge mounted on it. On the can it tells you what the low pressure should read based on the outside temp. What is the pressure in the system now. Warm air doesn't necessarily mean low freon but may be a mixing valve problem in the system.

 

after releasing some of the gas it is in the 24 to 45 range. Before I added refrigerant it was slightly below 25. I monitored the pressure while adding refrigerant. Seemed like it slowly increased then all of a sudden it spiked to over 45. That is when it stopped producing cool air. I released gas until it was back in the recommended range and it now is producing cool air. Will see how it works today. If still a problem I will take it in and get it serviced.

 

Lexus master tech here,

I hate to break the news to you, but i have seen way too many 2007-2009 ES350's with 100,000+ miles have low freon. The problem is a leaking evaporator core, and it's very expensive to replace. The cost is easily over $1500. I think i've done 2 this season so far.

 

Are the leaks significant? Or would it be better to just add the freon over time?

 

Even the Camry's of the same year have the same problem

 

Is that behind the dash. What is involved in replacing it?

 

Potentially good info here . If you are a master tech can you please see if you can get the data on how many of the millions of Lexus' have been sold have had this problem. I don't want to base a reliability issue on the 2 units you have replaced so far. Maybe a small sample would be how many evaps were replaced at your dealership over the last 5 years. That would be great info for the form.

 

People have the tendency to empty the AC refrigerant contents when it may only need half a can or other portion thereof. Use the gauge to monitor how much is needed to refill the AC system. Our ES' AC system is holding well. I've refilled it once and it only needed about 2/3'rds of the can. In my state it is illegal to discharge refrigerant into the atmosphere.

 

Sound like you need to turn yourself in to the enviro-police. If you need to add freon then you had to leak it out. So you violated the laws in your state. Use the gauges and you can't under or overfill the system.